JP2014199750A - Negative electrode carbon material for lithium secondary battery, negative electrode for lithium battery, and lithium secondary battery - Google Patents
Negative electrode carbon material for lithium secondary battery, negative electrode for lithium battery, and lithium secondary battery Download PDFInfo
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- JP2014199750A JP2014199750A JP2013074505A JP2013074505A JP2014199750A JP 2014199750 A JP2014199750 A JP 2014199750A JP 2013074505 A JP2013074505 A JP 2013074505A JP 2013074505 A JP2013074505 A JP 2013074505A JP 2014199750 A JP2014199750 A JP 2014199750A
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- Prior art keywords
- negative electrode
- graphite
- carbon material
- lithium
- electrode carbon
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- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
Description
本発明は、リチウム二次電池用負極炭素材料、リチウム電池用負極およびリチウム二次電池に関するものである。 The present invention relates to a negative electrode carbon material for a lithium secondary battery, a negative electrode for a lithium battery, and a lithium secondary battery.
リチウム二次電池は、エネルギー密度が高く、自己放電が少なく長期信頼性に優れる等の利点により、ノート型パソコンや携帯電話などの小型電子機器用の電池として広く実用化されている。近年では電子機器の高機能化や電気自動車への利用が進み、より性能の高いリチウム二次電池の開発が求められている。 Lithium secondary batteries have been widely put into practical use as batteries for small electronic devices such as notebook computers and mobile phones because of their advantages such as high energy density, low self-discharge and excellent long-term reliability. In recent years, advanced functions of electronic devices and use in electric vehicles have progressed, and development of lithium secondary batteries with higher performance has been demanded.
現在、リチウム二次電池の負極活物質としては、炭素材料が一般的であり、電池性能の向上のために種々な炭素材料が提案されている。 At present, carbon materials are generally used as negative electrode active materials for lithium secondary batteries, and various carbon materials have been proposed for improving battery performance.
例えば特許文献１には、シラン及びシロキサンから選ばれる有機珪素化合物を空隙を有する黒鉛に含浸させ、この有機珪素化合物の架橋物を形成し、これを加熱（非酸化性ガス中、６００〜１４００℃）してその架橋物を黒鉛と反応させることによって得られたＣ／Ｓｉ／Ｏ複合材料を電極活物質として用いた電気化学蓄電デバイスが記載されている。また、この電極活物質を特にリチウムイオン二次電池の負極に用いることで、高容量でかつサイクル特性に優れた電気化学デバイスを得ることができると記載されている。 For example, in Patent Document 1, an organosilicon compound selected from silane and siloxane is impregnated into graphite having voids to form a crosslinked product of this organosilicon compound, which is heated (in a non-oxidizing gas, at 600 to 1400 ° C. And an electrochemical storage device using a C / Si / O composite material obtained by reacting the cross-linked product with graphite as an electrode active material. Further, it is described that an electrochemical device having a high capacity and excellent cycle characteristics can be obtained by using this electrode active material particularly for a negative electrode of a lithium ion secondary battery.
特許文献２には、リチウムを吸収および放出することができ、外部表面から内部へわたる気孔を有する黒鉛コアと、この気孔内部に分散配置された金属ナノ粒子と、この気孔内部を満たす非晶質炭素を含むリチウム二次電池用負極活物質が記載されている。また、この負極活物質をリチウム二次電池に用いることにより、容量維持率と充放電効率が向上するこが記載されている。 Patent Document 2 discloses that a graphite core capable of absorbing and releasing lithium and having pores extending from the outer surface to the inside, metal nanoparticles dispersedly arranged in the pores, and an amorphous material filling the pores. A negative electrode active material for lithium secondary batteries containing carbon is described. Further, it is described that the capacity retention rate and the charge / discharge efficiency are improved by using this negative electrode active material for a lithium secondary battery.
特許文献３には、内部に空隙があり、かつ、リチウムと合金を形成する金属（ケイ素等）を含有する金属内包中空炭素粒子を含有する炭素材料が記載されている。この炭素粒子は、微細なグレイン（炭素からなるマトリックス）が多数寄せ集まって形成されており、グレイン同士の間隙に互いに繋がった複数の孔が形成されていることが記載され、この炭素粒子にはさらに黒鉛等の導電助剤を含有することができることが記載されている。また、このような炭素材料は、リチウムイオン二次電池の負極材料として好適であり、高いリチウム吸蔵放出容量を有し、かつ、連続充放電を行っても破損しにくいことが記載されている。 Patent Document 3 describes a carbon material containing metal-embedded hollow carbon particles containing voids inside and containing a metal (such as silicon) that forms an alloy with lithium. It is described that the carbon particles are formed by gathering a large number of fine grains (carbon matrix), and a plurality of pores connected to each other are formed in the gaps between the grains. It is further described that a conductive additive such as graphite can be contained. Further, it is described that such a carbon material is suitable as a negative electrode material for a lithium ion secondary battery, has a high lithium storage / release capacity, and is not easily damaged even if continuous charge / discharge is performed.
特許文献４には、負極活物質として黒鉛、正極活物質としてリチウムを吸蔵・放出可能な材料を用いた非水電解質二次電池であって、黒鉛の細孔直径が４〜１０ｎｍである細孔の容積と細孔直径が３０〜１００ｎｍである細孔の容積との比が特定の範囲にあり、前記黒鉛が５００〜１５００℃の温度で表面酸化処理されている、非水電解質二次電池が記載されている。このように黒鉛の表面を酸化処理することにより黒鉛の細孔分布を制御することにより、黒鉛粒子の比表面積を増加させることなく、充電負荷特性を向上させることができると記載されている。 Patent Document 4 discloses a nonaqueous electrolyte secondary battery using graphite as a negative electrode active material and a material capable of inserting and extracting lithium as a positive electrode active material, wherein the pore diameter of graphite is 4 to 10 nm. A non-aqueous electrolyte secondary battery in which the ratio of the volume of pores to the volume of pores having a pore diameter of 30 to 100 nm is in a specific range, and the graphite is surface-oxidized at a temperature of 500 to 1500 ° C. Have been described. It is described that the charge load characteristics can be improved without increasing the specific surface area of the graphite particles by controlling the pore distribution of the graphite by oxidizing the surface of the graphite in this way.
近年、リチウム二次電池には、高い容量特性が求められ、さらに放電後に短時間で入力できる高入力特性も求められている。負極炭素材料のなかでも結晶性の高い黒鉛系材料は反応容量が比較的高いが、黒鉛系材料を負極活物質に用いたリチウム二次電池の入力特性は満足できるものではなかった。 In recent years, lithium secondary batteries have been required to have high capacity characteristics, and also to have high input characteristics that can be input in a short time after discharging. Among negative electrode carbon materials, graphite materials with high crystallinity have a relatively high reaction capacity, but the input characteristics of lithium secondary batteries using graphite materials as negative electrode active materials have not been satisfactory.
本発明の目的は、上述した課題を解決することにあり、すなわち入力特性が改善されたリチウム二次電池が得られる負極炭素材料、並びにこれを用いたリチウム二次電池用負極およびリチウム二次電池を提供することにある。 An object of the present invention is to solve the above-described problems, that is, a negative electrode carbon material from which a lithium secondary battery with improved input characteristics can be obtained, and a negative electrode for a lithium secondary battery and a lithium secondary battery using the same. Is to provide.
本発明の一態様によれば、酸化グラフェン層平面にホールが形成された酸化黒鉛系材料からなるリチウム二次電池用負極炭素材料が提供される。 According to one embodiment of the present invention, there is provided a negative electrode carbon material for a lithium secondary battery made of a graphite oxide material in which holes are formed in the plane of the graphene oxide layer.
本発明の他の態様によれば、上記の負極炭素材料を含むリチウム二次電池用負極が提供される。 According to the other aspect of this invention, the negative electrode for lithium secondary batteries containing said negative electrode carbon material is provided.
本発明の他の態様によれば、上記の負極を含むリチウム二次電池が提供される。 According to another aspect of the present invention, a lithium secondary battery including the negative electrode is provided.
本発明の実施形態によれば、入力特性が改善されたリチウム二次電池が得られる負極炭素材料、並びにこれを用いたリチウム二次電池用負極およびリチウム二次電池を提供することができる。 According to the embodiments of the present invention, it is possible to provide a negative electrode carbon material from which a lithium secondary battery with improved input characteristics can be obtained, and a negative electrode for a lithium secondary battery and a lithium secondary battery using the same.
本発明の実施形態によるリチウム二次電池用負極炭素材料は、酸化黒鉛系材料からなり、通常の酸化黒鉛に比べてリチウム二次電池の入力特性を改善することができる。この酸化黒鉛系材料は、酸化されたグラフェン層平面（ベーサル面）にホールが形成されている。少なくとも表面側の酸化グラフェン層にホールが形成されていることが好ましい。このホールは、リチウムイオン（Ｌｉイオン）を通過させることができ、酸化グラフェン層間内へのＬｉイオンの経路（Ｌｉパス）として機能することができる。通常の黒鉛や酸化黒鉛では、Ｌｉイオンの層間内へのＬｉパスはエッジ面側からの経路にほぼ限られ、また、層間内の奥（グラフェン層平面方向の奥）に至るまでの距離が長く、そのため、リチウムとの反応量が多くなると、入力特性が低下していた。本実施形態による酸化黒鉛系材料においては、エッジ面側からのＬｉパスに加えて、グラフェン層平面にホールを有するため、Ｌｉパスが増加し、また酸化グラフェン層内の奥に至る経路が短くなる。その結果、リチウム二次電池の入力特性を向上することができる。また、ホールの形成により、Ｌｉ反応サイトが増加し、反応容量を増大させることができ、このような炭素材料を負極に用いることによりリチウム二次電池の容量特性を改善することができる。 The negative electrode carbon material for a lithium secondary battery according to an embodiment of the present invention is made of a graphite oxide-based material, and can improve the input characteristics of the lithium secondary battery as compared with normal graphite oxide. In this graphite oxide-based material, holes are formed in the plane (basal plane) of the oxidized graphene layer. It is preferable that holes are formed at least in the graphene oxide layer on the surface side. This hole can pass lithium ions (Li ions) and can function as a Li ion path (Li path) into the graphene oxide layer. In ordinary graphite and graphite oxide, the Li path into the interlayer of Li ions is almost limited to the path from the edge surface side, and the distance to the back of the interlayer (the back of the graphene layer in the plane direction) is long. Therefore, the input characteristics deteriorated when the amount of reaction with lithium increased. In the graphite oxide-based material according to the present embodiment, in addition to the Li path from the edge surface side, the graphene layer plane has holes, so the Li path increases and the path to the back in the graphene oxide layer is shortened. . As a result, the input characteristics of the lithium secondary battery can be improved. In addition, the formation of holes increases the number of Li reaction sites and can increase the reaction capacity. By using such a carbon material for the negative electrode, the capacity characteristics of the lithium secondary battery can be improved.
このようなホールは、結晶の表面側の酸化グラフェン層より内側の酸化グラフェン層平面にも形成されていることが好ましく、少なくとも表層から内側へ３層にホールが形成されていることがより好ましく、少なくとも表層から内側へ５層にホールが形成されていることがさらに好ましく、さらに多くの層（例えば１０層以上）にホールを形成することができる。結晶を構成する全ての酸化グラフェン層あるいはグラフェン層にホールを形成することができる。また、複数の酸化グラフェン層を貫通するようにホールを形成することもできる。内部の酸化グラフェン層平面のホールは、種々の方法で炭素材料を切断して断面を出し、ＴＥＭ、ＳＥＭ等の電子顕微鏡で観測することができる。このようなホールが形成されることにより、酸化グラフェン層の積層方向（グラフェン層平面に垂直方向）の奥へ至るＬｉパスが形成され、入力特性をより向上することができる。 Such holes are preferably also formed in the plane of the graphene oxide layer inside the graphene oxide layer on the surface side of the crystal, more preferably at least three holes are formed from the surface layer to the inside, It is more preferable that holes are formed in at least five layers from the surface layer to the inside, and holes can be formed in more layers (for example, 10 layers or more). Holes can be formed in all the graphene oxide layers or graphene layers constituting the crystal. Further, holes can be formed so as to penetrate a plurality of graphene oxide layers. The holes in the plane of the internal graphene oxide layer can be observed with an electron microscope such as TEM or SEM by cutting the carbon material by various methods to obtain a cross section. By forming such holes, a Li path is formed which extends to the back in the stacking direction of the graphene oxide layer (perpendicular to the graphene layer plane), and input characteristics can be further improved.
これらのホールの開口サイズは、入力特性の向上に寄与でき、他の特性を大きく劣化させない限り特に制限はないが、ナノメートルサイズからマイクロメートルサイズに設定でき、１０ｎｍ〜１０００ｎｍの範囲が好ましい。ここでナノメートルサイズとは１ｎｍを含む数ｎｍ〜数十ｎｍ（５０ｎｍ未満）を意味し、マイクロメートルサイズとは１μｍを含む数μｍ〜数十μｍ（５０μｍ未満）を意味する。例えば、リチウムイオンを十分に通過させる観点から、開口サイズは１０ｎｍ以上が好ましく、５０ｎｍ以上がより好ましく、１００ｎｍ以上がさらに好ましい。酸化黒鉛の特性を劣化させない点から、開口サイズは１０００ｎｍ（１μｍ）以下が好ましく、８００ｎｍ以下がより好ましく、５００ｎｍ以下がさらに好ましい。ここで、「開口サイズ」とは、開口の最大長さ（最大開口サイズ）を意味し、開口の輪郭を収容できる最小面積の円の直径に相当する。リチウムイオン通過等の十分なホール形成効果を得る点から、ホール開口の輪郭の内側に存在できる最大面積の円の直径に相当する開口サイズ（最小開口サイズ）もナノメートルサイズ以上に設定でき、１０ｎｍ〜１０００ｎｍの範囲が好ましく、１０ｎｍ以上がより好ましく、５０ｎｍ以上がさらに好ましく、１００ｎｍ以上が特に好ましい。 The opening size of these holes can contribute to the improvement of input characteristics and is not particularly limited as long as other characteristics are not greatly deteriorated, but can be set from nanometer size to micrometer size, and is preferably in the range of 10 nm to 1000 nm. Here, the nanometer size means several nanometers to several tens of nanometers (less than 50 nm) including 1 nm, and the micrometer size means several micrometers to several tens of micrometers (less than 50 μm) including 1 μm. For example, from the viewpoint of sufficiently passing lithium ions, the opening size is preferably 10 nm or more, more preferably 50 nm or more, and further preferably 100 nm or more. In view of not deteriorating the characteristics of graphite oxide, the opening size is preferably 1000 nm (1 μm) or less, more preferably 800 nm or less, and even more preferably 500 nm or less. Here, the “opening size” means the maximum length (maximum opening size) of the opening, and corresponds to the diameter of a circle having the smallest area that can accommodate the outline of the opening. From the viewpoint of obtaining a sufficient hole forming effect such as the passage of lithium ions, the opening size (minimum opening size) corresponding to the diameter of the circle of the maximum area that can exist inside the hole opening contour can be set to a nanometer size or more. The range of ˜1000 nm is preferable, 10 nm or more is more preferable, 50 nm or more is more preferable, and 100 nm or more is particularly preferable.
このような開口サイズを有するホールの数密度は、１０〜２００個／μｍ2の範囲にあることが好ましい。少なくとも表面側の酸化グラフェン層においてこの範囲の数密度のホールが形成されていることが好ましい。ホールの数密度が低すぎると十分な入力特性向上効果等のホール形成効果が得られず、逆にホールの数密度が高すぎると比表面積が大きくなりすぎて充放電時の副反応が生じやすくなり、充放電効率が低下する場合がある。 The number density of holes having such an opening size is preferably in the range of 10 to 200 / μm 2 . It is preferable that holes with a number density in this range be formed at least in the graphene oxide layer on the surface side. If the hole number density is too low, sufficient hole-forming effects such as an improvement in input characteristics cannot be obtained. Conversely, if the hole number density is too high, the specific surface area becomes too large and side reactions during charge / discharge are likely to occur. Thus, the charge / discharge efficiency may be reduced.
ホールの数密度は、酸化黒鉛系材料表面の電子顕微鏡画像において、表面の１μｍ×１μｍの領域を任意に１０カ所選び、各領域内で開口サイズが１０ｎｍ以上のホールの個数をカウントし、１０カ所における平均値（個数／μｍ2）として求めることができる。本実施形態によれば、表層から内部へ３層目程度はホールの数密度がほとんど変わらない酸化黒鉛系材料を形成することができる。また、表層から内部へ複数層を貫通するホールを形成することができ、３０層程度まで到達するホールを形成することもできる。その際、表層から内側へ奥にいくほど、ホールの開口径は小さくなり、数密度も低下する傾向がある。十分なホール形成効果を得る点から、少なくとも表層及びその内側のグラフェン層においてホールの数密度が上記の範囲にあることが好ましく、少なくとも表層から該表層を含む３層目までのグラフェン層においてホールの数密度が上記の範囲にあることがより好ましく、少なくとも表層から該表層を含む５層目までのグラフェン層においてホールの数密度が上記の範囲にあることがさらに好ましく、少なくとも表層から該表層を含む１０層目までのグラフェン層においてホールの数密度を上記の範囲にすることもできる。 For the number density of holes, in the electron microscope image of the surface of the graphite oxide-based material, arbitrarily select 10 areas of 1 μm × 1 μm area on the surface, and count the number of holes with an opening size of 10 nm or more in each area. The average value (number / μm 2 ) can be obtained. According to the present embodiment, it is possible to form a graphite oxide-based material in which the hole number density hardly changes in the third layer from the surface layer to the inside. Moreover, a hole penetrating a plurality of layers from the surface layer to the inside can be formed, and a hole reaching up to about 30 layers can also be formed. At that time, as it goes inward from the surface layer, the opening diameter of the hole becomes smaller and the number density tends to decrease. From the viewpoint of obtaining a sufficient hole forming effect, it is preferable that the number density of holes is in the above range at least in the surface layer and the graphene layer inside thereof, and in the graphene layers including at least the surface layer to the third layer including the surface layer, The number density is more preferably in the above range, and at least the number density of holes in the graphene layer from the surface layer to the fifth layer including the surface layer is more preferably in the above range, and at least from the surface layer to the surface layer is included. In the graphene layers up to the tenth layer, the number density of holes can be set in the above range.
また、ホールは酸化グラフェン層平面において全面にわたって形成されていることが好ましく、均一に分布していることがより好ましい。複数のホールの間隔（隣り合うホールの開口間の最小距離、平均値）は、１００ｎｍ〜１０００ｎｍの範囲にあることが好ましい。このようにホールが形成されていることにより、酸化黒鉛の特性による電池特性を損なうことなく、入力特性等のホール形成効果をより高めることができる。このようなホールは、酸化黒鉛に固有の開口部（欠陥）とは異なる。このホール間隔は、酸化黒鉛系材料表面の電子顕微鏡画像において、表面の１μｍ×１μｍの領域を任意に１０カ所選び、各領域内でホールの間隔を測定し、１０カ所における平均値として求めることができる。 Further, the holes are preferably formed over the entire surface in the plane of the graphene oxide layer, and more preferably uniformly distributed. The interval between the plurality of holes (minimum distance between the openings of adjacent holes, average value) is preferably in the range of 100 nm to 1000 nm. By forming the holes in this way, the hole forming effect such as input characteristics can be further enhanced without impairing the battery characteristics due to the characteristics of graphite oxide. Such holes are different from openings (defects) inherent to graphite oxide. The hole interval can be obtained as an average value at 10 locations by arbitrarily selecting 10 1 μm × 1 μm regions of the surface in the electron microscope image of the surface of the graphite oxide material and measuring the interval of the holes in each region. it can.
ホールが形成された酸化黒鉛を得るための方法としては、酸化黒鉛にホール形成処理を行う方法と、黒鉛にホール形成処理を行い、その後にその黒鉛を酸化して酸化黒鉛を得る方法が挙げられる。ホール形成の制御性の観点からは、黒鉛を酸化した後の酸化黒鉛にホールを形成することが好ましい。 Examples of a method for obtaining graphite oxide having holes formed therein include a method of performing hole formation treatment on graphite oxide and a method of performing hole formation treatment on graphite and then oxidizing the graphite to obtain graphite oxide. . From the viewpoint of controllability of hole formation, it is preferable to form holes in the oxidized graphite after oxidizing the graphite.
このホール形成処理においては、粉末状の酸化黒鉛（又は黒鉛）をアルカリ水系溶液で浸漬処理し、濾別等の固液分離後に熱処理を行う。 In this hole formation treatment, powdered graphite oxide (or graphite) is immersed in an alkaline aqueous solution, and heat treatment is performed after solid-liquid separation such as filtration.
アルカリ水系溶液としては、アルカリ金属化合物、アルカリ土類金属化合物等を水系溶媒に溶解したものを用いることができるが、ＫＯＨ水溶液が好ましい。ＫＯＨ等のアルカリ金属化合物、アルカリ土類金属化合物の濃度は、０．１Ｍ〜１０Ｍの範囲に設定できる。 As the alkaline aqueous solution, a solution in which an alkali metal compound, an alkaline earth metal compound or the like is dissolved in an aqueous solvent can be used, and a KOH aqueous solution is preferable. The concentrations of alkali metal compounds such as KOH and alkaline earth metal compounds can be set in the range of 0.1M to 10M.
アルカリ水系溶液への酸化黒鉛（又は黒鉛）の浸漬時間は、１分〜２４時間の範囲に設定でき、浸漬時は必要に応じて適宜攪拌を行うことができる。浸漬時のアルカリ水系溶液の温度は、１０℃〜６０℃の範囲に設定でき、２０℃〜５０℃の範囲が好ましい。 The immersion time of graphite oxide (or graphite) in the alkaline aqueous solution can be set in a range of 1 minute to 24 hours, and can be appropriately stirred as necessary during the immersion. The temperature of the alkaline aqueous solution at the time of immersion can be set in a range of 10 ° C to 60 ° C, and a range of 20 ° C to 50 ° C is preferable.
浸漬処理後の熱処理は、窒素雰囲気やアルゴン雰囲気等の不活性雰囲気で行うことができる。熱処理温度は４００℃〜１２００℃の範囲に設定でき、熱処理時間は０．５時間〜２４時間に設定できる。熱処理後、水洗し、乾燥を行ってホールが形成された炭素材料を得ることができる。 The heat treatment after the immersion treatment can be performed in an inert atmosphere such as a nitrogen atmosphere or an argon atmosphere. The heat treatment temperature can be set in the range of 400 ° C. to 1200 ° C., and the heat treatment time can be set in the range of 0.5 hour to 24 hours. After the heat treatment, it is washed with water and dried to obtain a carbon material in which holes are formed.
例えば、酸化黒鉛をＫＯＨ水溶液に浸漬すると、酸化グラフェン層上にその平面の全体にわたってＫＯＨ結晶が斑点状に分布して形成される。その後の熱処理時に、２ＫＯＨ＋Ｃ→２Ｋ＋Ｈ2Ｏ＋ＣＯで示される反応が起こり、ＫＯＨ結晶の形成位置の炭素が欠損し、またはその付近の炭素が欠損し、ＫＯＨ結晶のサイズと同じかそれ以上のサイズのホールが形成される。このような反応は内側の酸化グラフェン層においても順次進行し、内側の酸化グラフェン層にもホールを形成することができる。 For example, when graphite oxide is immersed in a KOH aqueous solution, KOH crystals are distributed in the form of spots on the entire surface of the graphene oxide layer. During the subsequent heat treatment, a reaction represented by 2KOH + C → 2K + H 2 O + CO occurs, the carbon at the formation position of the KOH crystal is deficient, or the carbon in the vicinity thereof is deficient, and the hole has a size equal to or larger than the size of the KOH crystal. Is formed. Such a reaction sequentially proceeds in the inner graphene oxide layer, and holes can be formed in the inner graphene oxide layer.
ホールの開口サイズ、数密度、分布は、ＫＯＨ結晶等の結晶のサイズや数密度、分布に依存し、ＫＯＨ等のアルカリ水系溶液の濃度や、浸漬時間、浸漬温度、浸漬時の攪拌等の浸漬条件によって制御でき、さらに、浸漬処理後の熱処理温度、熱処理時間、雰囲気等の熱処理条件によって制御することができる。このように酸化グラフェン層に形成されたホールは、酸化黒鉛に固有の開口部（一次粒子間の空隙や、欠陥、エッジ近傍の空隙や割れ）とは異なる。 The opening size, number density, and distribution of holes depend on the size, number density, and distribution of crystals such as KOH crystals, and the concentration of alkaline aqueous solution such as KOH, immersion time, immersion temperature, immersion during immersion, etc. It can be controlled depending on the conditions, and further can be controlled by the heat treatment conditions such as the heat treatment temperature, heat treatment time and atmosphere after the immersion treatment. Thus, the holes formed in the graphene oxide layer are different from the openings inherent to graphite oxide (voids between primary particles, defects, voids and cracks near edges).
上述のホール形成方法によれば酸化黒鉛の構造を著しく劣化させることなく、酸化グラフェン層にホールを形成することができるため、酸化黒鉛本来の特性による電池特性を大きく損なうことなく、リチウム二次電池の入力特性（あるいはさらに容量特性）を改善することができる。 According to the above hole formation method, holes can be formed in the graphene oxide layer without significantly degrading the structure of the graphite oxide, so that the lithium secondary battery can be obtained without greatly deteriorating the battery characteristics due to the original characteristics of the graphite oxide. The input characteristics (or further capacity characteristics) can be improved.
このように本実施形態によるホール形成後の酸化黒鉛系材料は、原料の黒鉛の酸化状態に応じた構造や物性を有することができる。 Thus, the graphite oxide-based material after hole formation according to the present embodiment can have a structure and physical properties according to the oxidation state of the raw material graphite.
本実施形態による酸化黒鉛系材料の形成に用いられる原料の黒鉛の（００２）面の面間隔ｄ002は０．３４０ｎｍ以下であることが好ましく、０．３３８以下であることがより好ましく、黒鉛のｄ002は０．３３５４であるため、本実施形態による酸化黒鉛系材料の形成に用いられる原料の黒鉛のｄ002は０．３３５４〜０．３４０の範囲にあることが好ましい。このｄ002はＸ線回折法（ＸＲＤ）により求めることができる。Ｌｃは５０ｎｍ以上が好ましく、１００ｎｍ以上がより好ましい。 Preferably the plane spacing d 002 of (002) plane of the graphite material used to form the oxide graphite material according to the present embodiment is less than 0.340 nm, more preferably 0.338 or less, graphite d 002 is because it is .3354, d 002 of graphite material used to form the oxide graphite material according to the present embodiment is preferably in the range of from 0.3354 to 0.340. This d 002 can be obtained by X-ray diffraction (XRD). Lc is preferably 50 nm or more, and more preferably 100 nm or more.
本実施形態による酸化黒鉛系材料の形成に用いられる原料の黒鉛は、充填効率や混合性、成形性等の点から、粒子状のものを用いることができる。粒子の形状としては、球状、楕円球状、鱗片状が挙げられる。一般的な球状化処理を行ってもよい。 The raw material graphite used for forming the graphite oxide-based material according to the present embodiment can be in the form of particles from the viewpoint of filling efficiency, mixing property, moldability, and the like. Examples of the shape of the particles include a spherical shape, an elliptical spherical shape, and a scale shape. A general spheroidizing treatment may be performed.
本実施形態による酸化黒鉛系材料の形成に用いられる原料の黒鉛の平均粒径は、充放電時の副反応を抑えて充放電効率の低下を抑える点から、１μｍ以上が好ましく、２μｍ以上がより好ましく、５μｍ以上がさらに好ましく、入出力特性の観点や電極作製上の観点（電極表面の平滑性等）から、４０μｍ以下が好ましく、３５μｍ以下がより好ましく、３０μｍ以下がさらに好ましい。ここで、平均粒径は、レーザー回折散乱法による粒度分布（体積基準）における積算値５０％での粒径（メジアン径：Ｄ50）を意味する。 The average particle diameter of the raw material graphite used for forming the graphite oxide-based material according to the present embodiment is preferably 1 μm or more, more preferably 2 μm or more from the viewpoint of suppressing side reactions during charge / discharge and suppressing a decrease in charge / discharge efficiency. It is preferably 5 μm or more, and is preferably 40 μm or less, more preferably 35 μm or less, and even more preferably 30 μm or less from the viewpoint of input / output characteristics and electrode manufacturing viewpoint (such as electrode surface smoothness). Here, the average particle diameter means the particle diameter (median diameter: D 50 ) at an integrated value of 50% in the particle size distribution (volume basis) by the laser diffraction scattering method.
本実施形態による酸化黒鉛系材料の形成に用いられる原料の黒鉛のＢＥＴ比表面積（窒素吸着法による７７Ｋでの測定に基づく）は、充放電時の副反応を抑えて充放電効率の低下を抑える点から、１０ｍ2／ｇ未満が好ましく、５ｍ2／ｇ以下がより好ましい。一方、十分な入出力特性を得る点から、ＢＥＴ比表面積は、０．５ｍ2／ｇ以上が好ましく、１ｍ2／ｇ以上がより好ましい。 The BET specific surface area of the raw material graphite used for forming the graphite oxide-based material according to the present embodiment (based on measurement at 77 K by the nitrogen adsorption method) suppresses side reactions during charge and discharge and suppresses a decrease in charge and discharge efficiency. from the point, preferably less than 10m 2 / g, 5m 2 / g or less is more preferable. On the other hand, from the viewpoint of obtaining sufficient input / output characteristics, the BET specific surface area is preferably 0.5 m 2 / g or more, and more preferably 1 m 2 / g or more.
本実施形態による酸化黒鉛系材料の形成に用いられる原料の黒鉛としては、天然黒鉛、人造黒鉛を用いることができる。人造黒鉛は、コークス等を黒鉛化して得られた通常の製品を使用することができる。また、人造黒鉛は２０００〜３２００℃の範囲で熱処理したものを用いることもできる。 As the raw material graphite used for forming the graphite oxide material according to the present embodiment, natural graphite or artificial graphite can be used. As the artificial graphite, a normal product obtained by graphitizing coke or the like can be used. Artificial graphite that has been heat-treated in the range of 2000 to 3200 ° C. can also be used.
酸化黒鉛は、結晶内部のグラフェン層まで酸化されたものであり、天然黒鉛または人造黒鉛を酸化処理することにより形成することができる。結晶を構成するグラフェン層のできるだけ多くが酸化されていることが好ましく、全てのグラフェン層が酸化されていることが好ましい。このようにグラフェン層が酸化されることにより、Ｌｉ反応サイトが増加し、反応容量を増大させることができる。また、酸化グラフェンの層間距離を大きくすることができ、Ｌｉイオンの拡散速度を増大できる。その結果、リチウム二次電池の容量特性および入力特性の向上に寄与できる。 Graphite oxide is oxidized up to the graphene layer inside the crystal, and can be formed by oxidizing natural graphite or artificial graphite. It is preferable that as much of the graphene layer constituting the crystal as possible is oxidized, and it is preferable that all the graphene layers are oxidized. As the graphene layer is oxidized in this way, the number of Li reaction sites is increased, and the reaction capacity can be increased. Moreover, the interlayer distance of graphene oxide can be increased, and the diffusion rate of Li ions can be increased. As a result, it is possible to contribute to improvement of capacity characteristics and input characteristics of the lithium secondary battery.
酸化黒鉛の酸素と炭素の元素比（Ｏ／Ｃ比）は、０．０１〜１の範囲にあることが好ましく、０．０１〜０．５の範囲にあることがより好ましく、０．０５〜０．５の範囲がさらに好ましく、０．０５〜０．３３の範囲が特に好ましい。Ｏ／Ｃ比が低すぎると、十分な酸化による効果が得られず、逆にＯ／Ｃ比が高すぎると、導電率が低下し、入力特性等の電池特性を損なう場合がある。 The oxygen to carbon element ratio (O / C ratio) of graphite oxide is preferably in the range of 0.01 to 1, more preferably in the range of 0.01 to 0.5, and 0.05 to A range of 0.5 is more preferable, and a range of 0.05 to 0.33 is particularly preferable. If the O / C ratio is too low, the effect of sufficient oxidation cannot be obtained. Conversely, if the O / C ratio is too high, the conductivity may be reduced, and battery characteristics such as input characteristics may be impaired.
結晶内部まで酸化された酸化黒鉛のＸＲＤパターンは、２θ＝２６°付近の（００２）に対応するピークが、黒鉛と比べ、低角度側に位置し、強度が小さくなり、ブロードになる。このような酸化黒鉛からなる負極炭素材料は、表面が自然酸化された黒鉛や酸素を含む官能基が結合した黒鉛等の通常の黒鉛とは区別される。 In the XRD pattern of graphite oxide oxidized to the inside of the crystal, the peak corresponding to (002) in the vicinity of 2θ = 26 ° is located on the lower angle side compared to graphite, the strength is reduced, and broadening occurs. Such a negative electrode carbon material made of graphite oxide is distinguished from normal graphite such as graphite having a naturally oxidized surface and graphite having a functional group containing oxygen bonded thereto.
酸化黒鉛を得るための酸化は、例えばＢｒｏｄｉｅ法やＭｏｄｉｆｉｅｄ Ｈｕｍｍｅｒｓ法等による酸化処理、酸化雰囲気下の熱処理により行うことができる。熱処理による酸化は、空気等の酸素含有雰囲気や、酸化性ガス含有雰囲気で行うことができる。熱処理温度は５００〜８００℃の範囲に設定でき、熱処理時間は０．５〜２４時間の範囲に設定できる。 The oxidation for obtaining graphite oxide can be performed by, for example, an oxidation treatment by a Brodie method, a Modified Hummers method, or the like, or a heat treatment in an oxidizing atmosphere. The oxidation by the heat treatment can be performed in an oxygen-containing atmosphere such as air or an oxidizing gas-containing atmosphere. The heat treatment temperature can be set in the range of 500 to 800 ° C., and the heat treatment time can be set in the range of 0.5 to 24 hours.
酸化黒鉛は、還元処理を行ってＯ／Ｃ比を上記範囲に調整することができる。還元処理は、例えば熱処理で行うことができる。この熱処理は窒素やアルゴンなどの不活性雰囲気で行うことができる。熱処理温度は５００〜１２００℃の範囲に設定でき、熱処理時間は０．５〜２４時間の範囲に形成できる。 Graphite oxide can be reduced to adjust the O / C ratio within the above range. The reduction treatment can be performed by heat treatment, for example. This heat treatment can be performed in an inert atmosphere such as nitrogen or argon. The heat treatment temperature can be set in the range of 500 to 1200 ° C., and the heat treatment time can be formed in the range of 0.5 to 24 hours.
本実施形態による酸化黒鉛系材料の酸化グラフェン層の層間距離は、ホール形成前の酸化黒鉛の構造に応じて設定することができる。この層間距離は、０．３４ｎｍ以上０．８ｎｍ未満の範囲にあることが好ましい。Ｌｉイオンの拡散速度を増大させる点から０．３４ｎｍ以上が好ましく、０．４ｎｍ以上がより好ましく、０．５ｎｍ以上がさらに好ましく、体積あたりのエネルギー密度の点から、０．８ｎｍ未満が好ましく、０．７８以下より好ましく、０．７以下がさらに好ましい。 The interlayer distance of the graphene oxide layer of the graphite oxide-based material according to the present embodiment can be set according to the structure of the graphite oxide before hole formation. This interlayer distance is preferably in the range of 0.34 nm or more and less than 0.8 nm. In terms of increasing the diffusion rate of Li ions, 0.34 nm or more is preferable, 0.4 nm or more is more preferable, 0.5 nm or more is more preferable, and in terms of energy density per volume, less than 0.8 nm is preferable, and 0 0.78 or less is more preferable, and 0.7 or less is more preferable.
本実施形態による酸化黒鉛系材料は、その酸化グラフェン層に、Ｌｉと合金化できる金属またはその酸化物を形成することができる。この金属または金属酸化物は、リチウムと反応可能であり、リチウム二次電池の充放電において電気化学的に活性なものである。このような金属または金属酸化物としては、Ｓｉ、Ｇｅ、Ｓｎ、Ｐｂ、Ａｌ、Ｇａ、Ｉｎ及びＭｇからなる群から選ばれる少なくとも一種の金属またはその酸化物を用いることができる。 The graphite oxide-based material according to the present embodiment can form a metal that can be alloyed with Li or an oxide thereof in the graphene oxide layer. This metal or metal oxide can react with lithium and is electrochemically active in charging / discharging of a lithium secondary battery. As such a metal or metal oxide, at least one metal selected from the group consisting of Si, Ge, Sn, Pb, Al, Ga, In, and Mg, or an oxide thereof can be used.
このような金属または金属酸化物は、酸化グラフェン層に形成されたホール周辺に形成されることが好ましい。 Such a metal or metal oxide is preferably formed around a hole formed in the graphene oxide layer.
このような金属または金属酸化物を形成することにより、反応容量を増大することができる。特に、金属または金属酸化物がホール周辺に形成されることにより、ホール周辺において、その他の部位と比べて金属または金属酸化物が強く結合でき、可逆性に優れるＬｉ反応サイトが増加し、反応容量を向上させることができる。 By forming such a metal or metal oxide, the reaction capacity can be increased. In particular, when a metal or metal oxide is formed around the hole, the metal or metal oxide can be strongly bonded to the periphery of the hole as compared with other parts, and the Li reaction sites with excellent reversibility are increased. Can be improved.
このような金属または金属酸化物の形成手法としては、ＣＶＤ、スパッタ、電解めっき、無電解めっき、水熱合成法などが挙げられる。 Examples of such a metal or metal oxide formation method include CVD, sputtering, electrolytic plating, electroless plating, and hydrothermal synthesis.
金属または金属酸化物の含有量は、酸化黒鉛系材料に対して０．１〜３０質量％が好ましい。この含有量が少なすぎると十分な含有効果がなく、この含有量が多すぎると、金属または金属酸化物の充放電時の体積膨張収縮の影響が大きく、炭素材料が劣化しやすくなる。 The content of the metal or metal oxide is preferably 0.1 to 30% by mass with respect to the graphite oxide material. If the content is too small, there is no sufficient content effect. If the content is too large, the influence of volume expansion / contraction during charging / discharging of the metal or metal oxide is large, and the carbon material is likely to deteriorate.
本実施形態による酸化黒鉛系材料は非晶質炭素で被覆することができる。これにより、炭素材料と電解液との副反応を抑制でき、充放電効率が向上し、反応容量を増大することができる。 The graphite oxide material according to the present embodiment can be coated with amorphous carbon. Thereby, the side reaction with a carbon material and electrolyte solution can be suppressed, charging / discharging efficiency can improve, and reaction capacity can be increased.
酸化黒鉛系材料への非晶質炭素の被覆方法としては、水熱合成法、ＣＶＤ、スパッタなどが挙げられる。 Examples of the method for coating the graphite oxide-based material with amorphous carbon include hydrothermal synthesis, CVD, and sputtering.
水熱合成法による酸化黒鉛系材料への非晶質炭素の被覆は、例えば次のようにして行うことができる。まず、酸化黒鉛系材料の粉末を炭素前駆体溶液に浸漬し、混合する。その後、真空ろ過を行って粉末を分離する。次に、分離された粉末を不活性雰囲気下で熱処理する。次いで、得られた粉末の凝集体を粉砕して所望の粒径に揃える。炭素前駆体溶液としては種々の糖溶液を用いることができ、特にスクロース水溶液が好ましい。この水溶液のスクロース濃度は０．１〜１０Ｍに設定でき、浸漬時間は１分〜２４時間に設定できる。熱処理は、窒素やアルゴン等の不活性雰囲気下で、４００〜１２００℃、０．５〜２４時間行うことができる。 The coating of amorphous carbon on the graphite oxide material by the hydrothermal synthesis method can be performed, for example, as follows. First, the graphite oxide material powder is immersed in a carbon precursor solution and mixed. Thereafter, vacuum filtration is performed to separate the powder. Next, the separated powder is heat-treated in an inert atmosphere. The powder agglomerates are then pulverized to the desired particle size. Various sugar solutions can be used as the carbon precursor solution, and an aqueous sucrose solution is particularly preferable. The sucrose concentration of this aqueous solution can be set to 0.1 to 10 M, and the immersion time can be set to 1 minute to 24 hours. The heat treatment can be performed at 400 to 1200 ° C. for 0.5 to 24 hours in an inert atmosphere such as nitrogen or argon.
以上に説明したホールが形成された酸化黒鉛系材料は、酸化グラフェン層にＬｉと合金化できる金属またはその酸化物が形成された上記構成と、酸化黒鉛系材料が非晶質炭素で被覆された上記構成のいずれか一方または両方を組み合わせた構成を備えることができる。 The above-described graphite oxide material in which holes are formed includes the above-described structure in which a graphene oxide layer is formed with a metal that can be alloyed with Li or its oxide, and the graphite oxide material is coated with amorphous carbon. The structure which combined either one or both of the said structures can be provided.
本実施形態による負極炭素材料は、充填効率や混合性、成形性等の点から、粒子状のものを用いることができる。粒子の形状としては、球状、楕円球状、鱗片状が挙げられる。一般的な球状化処理を行ってもよい。 As the negative electrode carbon material according to the present embodiment, a particulate material can be used from the viewpoint of filling efficiency, mixing property, moldability, and the like. Examples of the shape of the particles include a spherical shape, an elliptical spherical shape, and a scale shape. A general spheroidizing treatment may be performed.
本実施形態による負極炭素材料の平均粒径は、充放電時の副反応を抑えて充放電効率の低下を抑える点から、１μｍ以上が好ましく、２μｍ以上がより好ましく、５μｍ以上がさらに好ましく、入出力特性の観点や電極作製上の観点（電極表面の平滑性等）から、４０μｍ以下が好ましく、３５μｍ以下がより好ましく、３０μｍ以下がさらに好ましい。ここで、平均粒径は、レーザー回折散乱法による粒度分布（体積基準）における積算値５０％での粒径（メジアン径：Ｄ50）を意味する。 The average particle diameter of the negative electrode carbon material according to the present embodiment is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more, from the viewpoint of suppressing side reactions during charge / discharge and suppressing a decrease in charge / discharge efficiency. 40 μm or less is preferable, 35 μm or less is more preferable, and 30 μm or less is even more preferable from the viewpoint of output characteristics and electrode manufacturing (electrode surface smoothness and the like). Here, the average particle diameter means the particle diameter (median diameter: D 50 ) at an integrated value of 50% in the particle size distribution (volume basis) by the laser diffraction scattering method.
本実施形態による負極炭素材料のＢＥＴ比表面積（窒素吸着法による７７Ｋでの測定に基づく）は、充放電時の副反応を抑えて充放電効率の低下を抑える点から、１０ｍ2／ｇ未満が好ましく、５ｍ2／ｇ以下がより好ましい。一方、十分な入出力特性を得る点から、ＢＥＴ比表面積は、０．５ｍ2／ｇ以上が好ましく、１ｍ2／ｇ以上がより好ましい。 The BET specific surface area (based on measurement at 77 K by the nitrogen adsorption method) of the negative electrode carbon material according to the present embodiment is less than 10 m 2 / g from the viewpoint of suppressing side reactions during charge and discharge and suppressing the decrease in charge and discharge efficiency. Preferably, 5 m 2 / g or less is more preferable. On the other hand, from the viewpoint of obtaining sufficient input / output characteristics, the BET specific surface area is preferably 0.5 m 2 / g or more, and more preferably 1 m 2 / g or more.
以上に説明した負極炭素材料は、リチウムイオン二次電池の負極活物質に適用でき、この炭素材料を負極活物質として用いることにより入力特性が改善されたリチウムイオン二次電池を提供することができる。 The negative electrode carbon material described above can be applied to a negative electrode active material of a lithium ion secondary battery. By using this carbon material as a negative electrode active material, a lithium ion secondary battery with improved input characteristics can be provided. .
リチウムイオン二次電池用の負極は、例えば、負極集電体上に、この炭素材料からなる負極活物質と結着剤を含む負極活物質層を形成することで作製することができる。この負極活物質層は、一般的なスラリー塗布法で形成することができる。具体的には、負極活物質、結着剤および溶媒を含むスラリーを調製し、これを負極集電体上に塗布し、乾燥し、必要に応じて加圧することで、負極を得ることができる。負極スラリーの塗布方法としては、ドクターブレード法、ダイコーター法、ディップコーティング法が挙げられる。予め負極活物質層を形成した後に、蒸着、スパッタ等の方法でアルミニウム、ニッケルまたはそれらの合金の薄膜を集電体として形成して、負極を得ることもできる。 A negative electrode for a lithium ion secondary battery can be produced, for example, by forming a negative electrode active material layer including a negative electrode active material made of this carbon material and a binder on a negative electrode current collector. This negative electrode active material layer can be formed by a general slurry coating method. Specifically, a negative electrode can be obtained by preparing a slurry containing a negative electrode active material, a binder, and a solvent, applying the slurry onto a negative electrode current collector, drying, and pressing as necessary. . Examples of the method for applying the negative electrode slurry include a doctor blade method, a die coater method, and a dip coating method. After the negative electrode active material layer is formed in advance, a negative electrode can be obtained by forming a thin film of aluminum, nickel, or an alloy thereof as a current collector by a method such as vapor deposition or sputtering.
負極用の結着剤としては、特に制限されるものではないが、ポリフッ化ビニリデン（ＰＶｄＦ）、ビニリデンフルオライド−ヘキサフルオロプロピレン共重合体、ビニリデンフルオライド−テトラフルオロエチレン共重合体、スチレン−ブタジエン共重合ゴム、ポリテトラフルオロエチレン、ポリプロピレン、ポリエチレン、ポリイミド、ポリアミドイミド、メチル（メタ）アクリレート、エチル（メタ）アクリレート、ブチル（メタ）アクリレート、（メタ）アクリロニトリル、イソプレンゴム、ブタジエンゴム、フッ素ゴムが挙げられる。スラリー溶媒としては、Ｎ−メチル−２−ピロリドン（ＮＭＰ）や水を用いることができる。水を溶媒として用いる場合、さらに増粘剤として、カルボキシメチルセルロース、メチルセルロース、ヒドロキシメチルセルロース、エチルセルロース、ポリビニルアルコールを用いることができる。 The binder for the negative electrode is not particularly limited, but polyvinylidene fluoride (PVdF), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene. Copolymer rubber, polytetrafluoroethylene, polypropylene, polyethylene, polyimide, polyamideimide, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylonitrile, isoprene rubber, butadiene rubber, fluorine rubber Can be mentioned. As the slurry solvent, N-methyl-2-pyrrolidone (NMP) or water can be used. When water is used as a solvent, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, and polyvinyl alcohol can be used as a thickener.
この負極用の結着剤の含有量は、トレードオフの関係にある結着力とエネルギー密度の観点から、負極活物質１００質量部に対して０．１〜３０質量部の範囲にあることが好ましく、０．５〜２５質量部の範囲がより好ましく、１〜２０質量部の範囲がさらに好ましい。 The content of the binder for the negative electrode is preferably in the range of 0.1 to 30 parts by mass with respect to 100 parts by mass of the negative electrode active material from the viewpoint of the binding force and energy density that are in a trade-off relationship. The range of 0.5-25 mass parts is more preferable, and the range of 1-20 mass parts is more preferable.
負極集電体としては、特に制限されるものではないが、電気化学的な安定性から、銅、ニッケル、ステンレス、モリブデン、タングステン、タンタルおよびこれらの２種以上を含む合金が好ましい。その形状としては、箔、平板状、メッシュ状が挙げられる。 The negative electrode current collector is not particularly limited, but copper, nickel, stainless steel, molybdenum, tungsten, tantalum, and alloys containing two or more of these are preferable from the viewpoint of electrochemical stability. Examples of the shape include foil, flat plate, and mesh.
本発明の実施形態によるリチウムイオン二次電池は、上記負極と正極と電解質を含む。 The lithium ion secondary battery by embodiment of this invention contains the said negative electrode, a positive electrode, and electrolyte.
正極は、例えば、正極活物質、結着剤及び溶媒（さらに必要により導電補助材）を含むスラリーを調製し、これを正極集電体上に塗布し、乾燥し、必要に応じて加圧することにより、正極集電体上に正極活物質層を形成することにより作製できる。 For the positive electrode, for example, a slurry containing a positive electrode active material, a binder, and a solvent (and a conductive auxiliary material if necessary) is prepared, applied to the positive electrode current collector, dried, and pressurized as necessary. Thus, a positive electrode active material layer can be formed on the positive electrode current collector.
正極活物質としては、特に制限されるものではないが、例えば、リチウム複合酸化物やリン酸鉄リチウムなどを用いることができる。リチウム複合酸化物としては、マンガン酸リチウム（ＬｉＭｎ2Ｏ4）；コバルト酸リチウム（ＬｉＣｏＯ2）；ニッケル酸リチウム（ＬｉＮｉＯ2）；これらのリチウム化合物のマンガン、コバルト、ニッケルの部分の少なくとも一部をアルミニウム、マグネシウム、チタン、亜鉛など他の金属元素で置換したもの；マンガン酸リチウムのマンガンの一部を少なくともニッケルで置換したニッケル置換マンガン酸リチウム；ニッケル酸リチウムのニッケルの一部を少なくともコバルトで置換したコバルト置換ニッケル酸リチウム；ニッケル置換マンガン酸リチウムのマンガンの一部を他の金属（例えばアルミニウム、マグネシウム、チタン、亜鉛の少なくとも一種）で置換したもの；コバルト置換ニッケル酸リチウムのニッケルの一部を他の金属元素（例えばアルミニウム、マグネシウム、チタン、亜鉛の少なくとも一種）で置換したものが挙げられる。これらのリチウム複合酸化物は一種を単独で使用してもよいし、二種以上を混合して用いてもよい。正極活物質の平均粒径については、電解液との反応性やレート特性等の観点から、例えば平均粒径が０．１〜５０μｍの範囲にある正極活物質を用いることができ、好ましくは平均粒径が１〜３０μｍの範囲にある正極活物質、より好ましくは平均粒径が５〜２５μｍの範囲にあるものを用いることができる。ここで、平均粒径は、レーザー回折散乱法による粒度分布（体積基準）における積算値５０％での粒径（メジアン径：Ｄ50）を意味する。 Although it does not restrict | limit especially as a positive electrode active material, For example, lithium complex oxide, lithium iron phosphate, etc. can be used. Examples of the lithium composite oxide include lithium manganate (LiMn 2 O 4 ); lithium cobaltate (LiCoO 2 ); lithium nickelate (LiNiO 2 ); and at least part of the manganese, cobalt, and nickel portions of these lithium compounds. Replaced with other metal elements such as aluminum, magnesium, titanium, zinc; nickel-substituted lithium manganate in which part of manganese in lithium manganate is replaced with at least nickel; part of nickel in lithium nickelate is replaced with at least cobalt Cobalt-substituted lithium nickelate; a part of manganese in nickel-substituted lithium manganate substituted with another metal (for example, at least one of aluminum, magnesium, titanium, and zinc); a part of nickel in cobalt-substituted lithium nickelate other Metallic elements (e.g. aluminum, magnesium, titanium, at least one zinc) include those substituted with. These lithium composite oxides may be used individually by 1 type, and 2 or more types may be mixed and used for them. Regarding the average particle diameter of the positive electrode active material, for example, a positive electrode active material having an average particle diameter in the range of 0.1 to 50 μm can be used from the viewpoint of reactivity with the electrolytic solution, rate characteristics, and the like. A positive electrode active material having a particle diameter in the range of 1 to 30 μm, more preferably an average particle diameter in the range of 5 to 25 μm can be used. Here, the average particle diameter means the particle diameter (median diameter: D 50 ) at an integrated value of 50% in the particle size distribution (volume basis) by the laser diffraction scattering method.
正極用の結着剤としては、特に制限されるものではないが、負極用結着剤と同様のものを用いることができる。中でも、汎用性や低コストの観点から、ポリフッ化ビニリデンが好ましい。正極用の結着剤の含有量は、トレードオフの関係にある結着力とエネルギー密度の観点から、正極活物質１００質量部に対して１〜２５質量部の範囲が好ましく、２〜２０質量部の範囲がより好ましく、２〜１０質量部の範囲がさらに好ましい。ポリフッ化ビニリデン（ＰＶｄＦ）以外の結着剤としては、ビニリデンフルオライド−ヘキサフルオロプロピレン共重合体、ビニリデンフルオライド−テトラフルオロエチレン共重合体、スチレン−ブタジエン共重合ゴム、ポリテトラフルオロエチレン、ポリプロピレン、ポリエチレン、ポリイミド、ポリアミドイミドが挙げられる。スラリー溶媒としては、Ｎ−メチル−２−ピロリドン（ＮＭＰ）を用いることができる。 Although it does not restrict | limit especially as a binder for positive electrodes, The thing similar to the binder for negative electrodes can be used. Among these, polyvinylidene fluoride is preferable from the viewpoint of versatility and low cost. The content of the binder for the positive electrode is preferably in the range of 1 to 25 parts by mass with respect to 100 parts by mass of the positive electrode active material, from the viewpoint of the binding force and energy density in a trade-off relationship, and 2 to 20 parts by mass. The range of 2-10 mass parts is more preferable. As binders other than polyvinylidene fluoride (PVdF), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene copolymer rubber, polytetrafluoroethylene, polypropylene, Examples include polyethylene, polyimide, and polyamideimide. As the slurry solvent, N-methyl-2-pyrrolidone (NMP) can be used.
正極集電体としては、特に制限されるものではないが、電気化学的な安定性の観点から、例えば、アルミニウム、チタン、タンタル、ステンレス鋼（ＳＵＳ）、その他のバルブメタル、又はそれらの合金を用いることができる。その形状としては、箔、平板状、メッシュ状が挙げられる。特にアルミニウム箔を好適に用いることができる。 The positive electrode current collector is not particularly limited, but from the viewpoint of electrochemical stability, for example, aluminum, titanium, tantalum, stainless steel (SUS), other valve metals, or alloys thereof are used. Can be used. Examples of the shape include foil, flat plate, and mesh. In particular, an aluminum foil can be suitably used.
正極の作製に際して、インピーダンスを低下させる目的で、導電補助材を添加してもよい。導電補助材としては、グラファイト、カーボンブラック、アセチレンブラック等の炭素質微粒子が挙げられる。 In the production of the positive electrode, a conductive auxiliary material may be added for the purpose of reducing the impedance. Examples of the conductive auxiliary material include carbonaceous fine particles such as graphite, carbon black, and acetylene black.
電解質としては、１種又は２種以上の非水溶媒に、リチウム塩を溶解させた非水系電解液を用いることができる。非水溶媒としては、特に制限されるものではないが、例えばエチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、ブチレンカーボネート（ＢＣ）、ビニレンカーボネート（ＶＣ）などの環状カーボネート；ジメチルカーボネート（ＤＭＣ）、ジエチルカーボネート（ＤＥＣ）、エチルメチルカーボネート（ＥＭＣ）、ジプロピルカーボネート（ＤＰＣ）などの鎖状カーボネート；ギ酸メチル、酢酸メチル、プロピオン酸エチルなどの脂肪族カルボン酸エステル；γ−ブチロラクトンなどのγ−ラクトン；１，２−エトキシエタン（ＤＥＥ）、エトキシメトキシエタン（ＥＭＥ）などの鎖状エーテル；テトラヒドロフラン、２−メチルテトラヒドロフランなどの環状エーテルが挙げられる。その他、非水溶媒として、ジメチルスルホキシド、１，３−ジオキソラン、ジオキソラン誘導体、ホルムアミド、アセトアミド、ジメチルホルムアミド、アセトニトリル、プロピオニトリル、ニトロメタン、エチルモノグライム、リン酸トリエステル、トリメトキシメタン、スルホラン、メチルスルホラン、１，３−ジメチル−２−イミダゾリジノン、３−メチル−２−オキサゾリジノン、プロピレンカーボネート誘導体、テトラヒドロフラン誘導体、エチルエーテル、１，３−プロパンサルトン、アニソール、Ｎ−メチルピロリドンなどの非プロトン性有機溶媒を用いることもできる。 As the electrolyte, a non-aqueous electrolyte solution in which a lithium salt is dissolved in one or two or more non-aqueous solvents can be used. Although it does not restrict | limit especially as a nonaqueous solvent, For example, cyclic carbonates, such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and vinylene carbonate (VC); Dimethyl carbonate (DMC), Chain carbonates such as diethyl carbonate (DEC), ethyl methyl carbonate (EMC) and dipropyl carbonate (DPC); aliphatic carboxylic acid esters such as methyl formate, methyl acetate and ethyl propionate; γ-lactones such as γ-butyrolactone Chain ethers such as 1,2-ethoxyethane (DEE) and ethoxymethoxyethane (EME); cyclic ethers such as tetrahydrofuran and 2-methyltetrahydrofuran. Other non-aqueous solvents include dimethyl sulfoxide, 1,3-dioxolane, dioxolane derivatives, formamide, acetamide, dimethylformamide, acetonitrile, propionitrile, nitromethane, ethyl monoglyme, phosphate triester, trimethoxymethane, sulfolane, methyl Non-protons such as sulfolane, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethyl ether, 1,3-propane sultone, anisole, N-methylpyrrolidone An organic solvent can also be used.
非水溶媒に溶解させるリチウム塩としては、特に制限されるものではないが、例えばＬｉＰＦ6、ＬｉＡｓＦ6、ＬｉＡｌＣｌ4、ＬｉＣｌＯ4、ＬｉＢＦ4、ＬｉＳｂＦ6、ＬｉＣＦ3ＳＯ3、ＬｉＣＦ3ＣＯ2、Ｌｉ（ＣＦ3ＳＯ2）2、ＬｉＮ（ＣＦ3ＳＯ2）2、リチウムビスオキサラトボレートが挙げられる。これらのリチウム塩は、一種を単独で、または二種以上を組み合わせて使用することができる。また、非水系電解液の代わりにポリマー電解質を用いてもよい。 Examples of the lithium salt dissolved in the nonaqueous solvent, is not particularly limited, for example LiPF 6, LiAsF 6, LiAlCl 4 , LiClO 4, LiBF 4, LiSbF 6, LiCF 3 SO 3, LiCF 3 CO 2, Li (CF 3 SO 2) 2, LiN (CF 3 SO 2) 2, include lithium Bisuo Kisara oxalatoborate. These lithium salts can be used individually by 1 type or in combination of 2 or more types. Further, a polymer electrolyte may be used instead of the non-aqueous electrolyte solution.
正極と負極との間にはセパレータを設けることができる。このセパレータとしては、ポリプロピレン、ポリエチレン等のポリオレフィン、ポリフッ化ビニリデン等のフッ素樹脂、ポリイミド等からなる多孔性フィルムや織布、不織布を用いることができる。 A separator can be provided between the positive electrode and the negative electrode. As this separator, a porous film, a woven fabric, or a nonwoven fabric made of a polyolefin such as polypropylene or polyethylene, a fluororesin such as polyvinylidene fluoride, polyimide, or the like can be used.
電池形状としては、円筒形、角形、コイン型、ボタン型、ラミネート型が挙げられる。ラミネート型の場合、正極、セパレータ、負極および電解質を収容する外装体としてラミネートフィルムを用いることが好ましい。このラミネートフィルムは、樹脂基材と、金属箔層、熱融着層（シーラント）を含む。この樹脂基材としては、ポリエステルやナイロンが挙げられ、この金属箔層としては、アルミニウム、アルミニウム合金、チタン箔が挙げられる。熱溶着層の材質としては、ポリエチレン、ポリプロピレン、ポリエチレンテレフタレート等の熱可塑性高分子材料が挙げられる。また、樹脂基材層や金属箔層はそれぞれ１層に限定されるものではなく２層以上であってもよい。汎用性やコストの観点から、アルミニウムラミネートフィルムが好ましい。 Examples of the battery shape include a cylindrical shape, a square shape, a coin shape, a button shape, and a laminate shape. In the case of a laminate type, it is preferable to use a laminate film as an exterior body that accommodates a positive electrode, a separator, a negative electrode, and an electrolyte. The laminate film includes a resin base material, a metal foil layer, and a heat seal layer (sealant). Examples of the resin base material include polyester and nylon, and examples of the metal foil layer include aluminum, an aluminum alloy, and a titanium foil. Examples of the material for the heat welding layer include thermoplastic polymer materials such as polyethylene, polypropylene, and polyethylene terephthalate. Moreover, the resin base material layer and the metal foil layer are not limited to one layer, and may be two or more layers. From the viewpoint of versatility and cost, an aluminum laminate film is preferable.
正極と負極とこれらの間に配置されたセパレータは、ラミネートフィルム等からなる外装容器に収容され、電解液が注入され、封止される。複数の電極対が積層された電極群が収容された構造とすることもできる。 The positive electrode, the negative electrode, and a separator disposed between them are accommodated in an outer container made of a laminate film or the like, and an electrolyte is injected and sealed. A structure in which an electrode group in which a plurality of electrode pairs are stacked can be accommodated.
（比較例１：酸化黒鉛の調製）
人造黒鉛（平均粒径２０μｍ、比表面積２ｍ2／ｇ）の粉末と硝酸ナトリウムを等量（質量比）とり、９８％硫酸を投入して撹拌後、氷冷下で過マンガン酸カリウムを投入し、２時間放置後、室温で１２時間撹拌した。次に、水で希釈し、６０℃程度まで放冷した後、３０％過酸化水素水を投入し、室温になるまで撹拌した。得られた酸化黒鉛を、水洗し、真空ろ過後、７０℃で２４時間真空乾燥を行った。
(Comparative Example 1: Preparation of graphite oxide)
Take artificial graphite (average particle size 20μm, specific surface area 2m 2 / g) powder and sodium nitrate in equal amounts (mass ratio), add 98% sulfuric acid and stir, then add potassium permanganate under ice cooling. After standing for 2 hours, the mixture was stirred at room temperature for 12 hours. Next, after diluting with water and allowing to cool to about 60 ° C., 30% aqueous hydrogen peroxide was added and stirred until it reached room temperature. The obtained graphite oxide was washed with water, vacuum filtered, and vacuum dried at 70 ° C. for 24 hours.
（実施例１）
比較例１と同様にして得た酸化黒鉛の粉末を７Ｍ ＫＯＨ水溶液に室温で１２時間浸漬した。その後、真空ろ過により固形分を分離し、これを窒素雰囲気下で８００℃１時間熱処理を行った。これを水洗した後、７０℃２４時間乾燥を行って、ホールが形成された酸化黒鉛系材料を得た。
Example 1
The graphite oxide powder obtained in the same manner as in Comparative Example 1 was immersed in a 7M KOH aqueous solution at room temperature for 12 hours. Then, solid content was isolate | separated by vacuum filtration and this was heat-processed at 800 degreeC for 1 hour by nitrogen atmosphere. This was washed with water and then dried at 70 ° C. for 24 hours to obtain a graphite oxide material having holes formed therein.
（実施例２）
実施例１と同様にして得た酸化黒鉛系材料の粉末を、１Ｍスクロース水溶液に浸漬し、ミキサーで１０分混合した。その後、真空ろ過により固形分を分離し、その固形分を窒素雰囲気下で１０００℃３時間の熱処理を行って、非晶質炭素で被覆された酸化黒鉛系材料の凝集体を得た。得られた凝集体を粉砕して、所定の平均粒径を有する酸化黒鉛系材料を得た。
(Example 2)
The graphite oxide material powder obtained in the same manner as in Example 1 was immersed in a 1M aqueous sucrose solution and mixed for 10 minutes with a mixer. Thereafter, the solid content was separated by vacuum filtration, and the solid content was subjected to a heat treatment at 1000 ° C. for 3 hours in a nitrogen atmosphere to obtain an aggregate of graphite oxide-based material coated with amorphous carbon. The obtained aggregate was pulverized to obtain a graphite oxide material having a predetermined average particle size.
（酸化状態Ｏ／Ｃ比の測定）
得られた酸化黒鉛のＯ／Ｃ比はＸ線光電子分光分析法（ＸＰＳ）で測定した。結果を表１に示す。
(Measurement of oxidation state O / C ratio)
The O / C ratio of the obtained graphite oxide was measured by X-ray photoelectron spectroscopy (XPS). The results are shown in Table 1.
（充放電試験）
酸化黒鉛と導電剤（カーボンブラック）と結着剤（ＰＶｄＦ）を、酸化黒鉛：導電剤：結着剤＝９２：１：７の質量比率で混合し、ＮＭＰに分散させてスラリーを作製した。このスラリーを銅箔上に塗布し、乾燥、圧延した後、２２×２５ｍｍに切り出して電極を得た。この電極を作用極とし、セパレータを挟んで対極のＬｉ箔と組み合わせて積層体を得た。この積層体と電解液（１ＭのＬｉＰＦ6を含むＥＣとＤＥＣの混合溶液、容量比ＥＣ／ＤＥＣ＝３／７）をアルミラミネート容器内に封入し、電池を作製した。
(Charge / discharge test)
Graphite oxide, a conductive agent (carbon black), and a binder (PVdF) were mixed at a mass ratio of graphite oxide: conductive agent: binder = 92: 1: 7 and dispersed in NMP to prepare a slurry. The slurry was applied on a copper foil, dried and rolled, and then cut into 22 × 25 mm to obtain an electrode. This electrode was used as a working electrode, and a laminate was obtained by combining with a counter electrode Li foil across a separator. This laminate and an electrolytic solution (a mixed solution of EC and DEC containing 1M LiPF 6 , volume ratio EC / DEC = 3/7) were sealed in an aluminum laminate container to produce a battery.
所定の電流値で、対極に対する作用極の電位が０Ｖまで充電（作用極にＬｉを挿入）し、２．０Ｖまで放電（作用極からＬｉを脱離）した。この充放電時の電流値は、作用極の放電容量を１時間で流す電流値を１Ｃとし、１サイクル目および２サイクル目の充放電は０．１Ｃ充電−０．１Ｃ放電とし、３サイクル目は０．５Ｃ充電−０．１Ｃ放電とした。 At a predetermined current value, the potential of the working electrode with respect to the counter electrode was charged to 0 V (Li was inserted into the working electrode), and discharged to 2.0 V (Li was desorbed from the working electrode). The current value at the time of charging / discharging is such that the current value for flowing the discharge capacity of the working electrode in 1 hour is 1C, and charging / discharging in the first and second cycles is 0.1C charging-0.1C discharging. Was 0.5 C charge-0.1 C discharge.
充放電特性として、初期放電容量（１サイクル目の放電容量）、充電レート特性（３サイクル目の放電容量／２サイクル目の放電容量）を求めた。結果を表１に示す。 As the charge / discharge characteristics, an initial discharge capacity (discharge capacity at the first cycle) and a charge rate characteristic (discharge capacity at the third cycle / discharge capacity at the second cycle) were obtained. The results are shown in Table 1.
表１に示されるように、酸化グラフェン層平面にホールが形成された酸化黒鉛系材料を用いることにより、容量特性とともに充電レート特性が向上することがわかる。また、実施例１の酸化黒鉛系材料を非晶質炭素で被覆した実施例２の黒鉛系材料を用いることにより、実施例１に対して容量特性および充電レート特性が改善されることがわかる。 As shown in Table 1, it can be seen that the charge rate characteristics as well as the capacity characteristics are improved by using a graphite oxide material in which holes are formed on the plane of the graphene oxide layer. Further, it can be seen that the capacity characteristics and the charge rate characteristics are improved with respect to Example 1 by using the graphite material of Example 2 in which the graphite oxide material of Example 1 is coated with amorphous carbon.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015156358A (en) * | 2014-02-20 | 2015-08-27 | 深▲セン▼市貝特瑞新能源材料股▲ふん▼有限公司 | Method for producing graphene based composite negative electrode material, negative electrode material produced thereby, and lithium ion secondary battery |
| WO2017047280A1 (en) * | 2015-09-16 | 2017-03-23 | 日本電気株式会社 | Lithium secondary battery and method for producing same |
| KR20180034005A (en) * | 2016-09-27 | 2018-04-04 | 한국전기연구원 | Negative Electrode Materials For Sodium Secondary Batteries And Producing Method Of The Same |
| JP2018097935A (en) * | 2016-12-08 | 2018-06-21 | 株式会社豊田中央研究所 | Carbonaceous material, lithium secondary battery, and method of producing carbonaceous material |
| KR20180114715A (en) * | 2017-04-11 | 2018-10-19 | 한국과학기술원 | Porous hetero nano structure, preparation method thereof, and lithium ion battery having the same |
| JP2018185931A (en) * | 2017-04-25 | 2018-11-22 | トヨタ自動車株式会社 | Negative electrode active material particles for lithium ion secondary battery and manufacturing method thereof |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1040914A (en) * | 1996-05-23 | 1998-02-13 | Sharp Corp | Manufacture of nonaqueous secondary battery and negative pole active substance |
| JPH10284080A (en) * | 1997-02-04 | 1998-10-23 | Mitsubishi Chem Corp | Lithium ion secondary battery |
| WO2011122297A1 (en) * | 2010-03-29 | 2011-10-06 | 日本ゼオン株式会社 | Lithium-ion secondary battery |
| US20120288750A1 (en) * | 2011-05-12 | 2012-11-15 | Northwestern University | Graphene materials having randomly distributed two-dimensional structural defects |
| JP2013028526A (en) * | 2011-06-24 | 2013-02-07 | Semiconductor Energy Lab Co Ltd | Multilayer graphene and power storage device |
-
2013
- 2013-03-29 JP JP2013074505A patent/JP2014199750A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1040914A (en) * | 1996-05-23 | 1998-02-13 | Sharp Corp | Manufacture of nonaqueous secondary battery and negative pole active substance |
| JPH10284080A (en) * | 1997-02-04 | 1998-10-23 | Mitsubishi Chem Corp | Lithium ion secondary battery |
| WO2011122297A1 (en) * | 2010-03-29 | 2011-10-06 | 日本ゼオン株式会社 | Lithium-ion secondary battery |
| US20120288750A1 (en) * | 2011-05-12 | 2012-11-15 | Northwestern University | Graphene materials having randomly distributed two-dimensional structural defects |
| JP2013028526A (en) * | 2011-06-24 | 2013-02-07 | Semiconductor Energy Lab Co Ltd | Multilayer graphene and power storage device |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015156358A (en) * | 2014-02-20 | 2015-08-27 | 深▲セン▼市貝特瑞新能源材料股▲ふん▼有限公司 | Method for producing graphene based composite negative electrode material, negative electrode material produced thereby, and lithium ion secondary battery |
| WO2017047280A1 (en) * | 2015-09-16 | 2017-03-23 | 日本電気株式会社 | Lithium secondary battery and method for producing same |
| JPWO2017047280A1 (en) * | 2015-09-16 | 2018-06-28 | 日本電気株式会社 | Lithium secondary battery and manufacturing method thereof |
| KR20180034005A (en) * | 2016-09-27 | 2018-04-04 | 한국전기연구원 | Negative Electrode Materials For Sodium Secondary Batteries And Producing Method Of The Same |
| KR102582118B1 (en) * | 2016-09-27 | 2023-09-25 | 한국전기연구원 | Negative Electrode Materials For Sodium Secondary Batteries And Producing Method Of The Same |
| JP2018097935A (en) * | 2016-12-08 | 2018-06-21 | 株式会社豊田中央研究所 | Carbonaceous material, lithium secondary battery, and method of producing carbonaceous material |
| KR20180114715A (en) * | 2017-04-11 | 2018-10-19 | 한국과학기술원 | Porous hetero nano structure, preparation method thereof, and lithium ion battery having the same |
| KR101975540B1 (en) | 2017-04-11 | 2019-05-07 | 한국과학기술원 | Porous hetero nano structure, preparation method thereof, and lithium ion battery having the same |
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| KR20200089448A (en) * | 2019-01-17 | 2020-07-27 | 주식회사 엘지화학 | Negative electrode active material for secondary battery, negative electrode including same and manufacturing method thereof |
| KR102475986B1 (en) | 2019-01-17 | 2022-12-09 | 주식회사 엘지에너지솔루션 | Negative electrode active material for secondary battery, negative electrode including same and manufacturing method thereof |
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