CN104923776A - Method for surface modification of AB3 hydrogen storage alloy by using aniline - Google Patents

Abstract

The invention discloses a method for surface modification of an AB3 hydrogen storage alloy by using aniline. An La0.94Mg0.06Ni3.49Co0.73Mn0.12A10.20 alloy is prepared through a vacuum induction smelting method; after an alloy ingot is mechanically crushed, the alloy ingot is screened to particle powder of 200-300 meshes by a ball mill; the alloy particle powder is put in a prepared solution; and the solution contains 0.25 mol/L of aniline, 2*10-3 mol/L of H2SO4 and 0.25 mol/L of ammonium persulfate, and is magnetically stirred for 10 minutes, washed, filteed and dried to obtain a modified alloy. The method is simple in operation and liable to be promoted, uses the aniline for surface modification of the AB3 hydrogen storage alloy for a Ni/MH battery cathode material with excellent application foreground, and obtains an alloy electrode material with excellent circulating performance and excellent dynamics performance.

Description

One utilizes aniline surface modification AB 3the method of type hydrogen storage alloy

Technical field

The invention belongs to metallurgical chemistry and electrochemical research field, particularly one utilizes aniline to AB ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20hydrogen bearing alloy carries out the method for surface modification.

Background technology

Current commercial Ni/MH battery can not meet high-energy-density, powerful requirement, especially the demand of the power supply such as electric bicycle, electric automobile and hybrid electric vehicle.Therefore develop more high power capacity, important directions that better cyclical stability, the Ni/MH battery that more high-power and combination property is desirable are current research.So far, as novel High-capacity hydrogen storage alloy electrode material, AB ₃type R-Mg-Ni alloy (R is rare earth or Y, Ca) has been carried out large quantity research.The discharge capacity of R-Mg-Ni alloy at the temperature of gentleness is than commercial AB ₅the mixed rare earths-based alloy of type improves about 30 ~ 40%.But, because this kind of alloy surface easily forms surface film oxide, the diffusion velocity of surperficial electro catalytic activity, electric conductivity, exchange current density and hydrogen etc. are all lower, and the capacity attenuation of electrode is very fast, high-rate discharge ability is poor, and their practical application is restricted.So far, one kettle way is adopted to utilize aniline while the polyaniline that compositing conducting is good, to AB ₃type hydrogen storage alloy carries out the rarely seen report of research of surface modification.

Summary of the invention

The object of this invention is to provide one and utilize aniline surface modification AB ₃the method of type hydrogen storage alloy.

Thinking of the present invention: carry out surface modification by one kettle way, puts into (the aniline, 2 × 10 consisted of containing 0.25 mol/L of solution in the solution prepared by hydrogen bearing alloy ^-3the H of mol/L ₂sO ₄with the ammonium persulfate of 0.25 mol/L), magnetic agitation 10min is to AB ₃type hydrogen storage alloy carries out surface modification, and aniline can polymerisation be polyaniline, by the modifying function of polyaniline, suppresses the corrosion of alloying component in high concentration KOH solution, improves AB ₃the cycle performance of type hydrogen storage alloy electrode.

Concrete steps are:

(1) AB is prepared by vacuum induction melting method ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20precursor alloy, after alloy pig mechanical crushing, with rotating speed 250 ~ 300 revs/min of ball millings 60 ~ 90 minutes, sieves out 200 ~ 300 object La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder.

(2) aniline, H is weighed ₂sO ₄be added to the water with ammonium persulfate, be mixed with solution, the aniline, 2 × 10 consisted of containing 0.25 mol/L of solution ^-3the H of mol/L ₂sO ₄with the ammonium persulfate of 0.25 mol/L.

(3) by La obtained for step (1) _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder is put in the solution that step (2) prepares, magnetic agitation 10 minutes, washing, and suction filtration is dry, the obtained AB utilizing aniline surface modification ₃type hydrogen storage alloy.

The inventive method is simple to operate, is easy to promote, and is beneficial to aniline to the Ni/MH cell negative electrode material AB with applications well prospect ₃type hydrogen storage alloy carries out surface modification, obtains the alloy electrode material with good circulation performance and excellent dynamic performance.

Detailed description of the invention

embodiment:

(1) AB is prepared by vacuum induction melting method ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20precursor alloy, after alloy pig mechanical crushing, with rotating speed 300 revs/min of ball millings 60 minutes, sieves out 300 object La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder.

(2) aniline, H is weighed ₂sO ₄be added to the water with ammonium persulfate, be mixed with solution, the aniline, 2 × 10 consisted of containing 0.25 mol/L of solution ^-3the H of mol/L ₂sO ₄with the ammonium persulfate of 0.25 mol/L.

(3) by La obtained for step (1) _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder is put in the solution that step (2) prepares, magnetic agitation 10 minutes, washing, and suction filtration is dry, the obtained AB utilizing aniline surface modification ₃type hydrogen storage alloy.

The obtained modification AB of the present embodiment is measured respectively with XRD technology, LAND 5.3B battery test system and CHI660E electrochemical workstation ₃the phase structure of type hydrogen storage alloy, cyclical stability and dynamic performance, result is as follows:

1) alloy is after aniline modified process, and the maximum discharge capacity of alloy electrode is changed.Maximum discharge capacity reduces to 307.8 mAh/g by 346.4 mAh/g time unmodified.

2) alloy is after polyaniline-modified process, and cyclical stability is improved.After 50 circulations, circulation volume conservation rate is increased to 82.6% from 69.5% time unmodified, i.e. AB ₃type alloy is after polyaniline-modified process, and the cycle performance of electrode improves.

3) AB of aniline surface modification is utilized ₃type hydrogen storage alloy exchange current density, limiting current density all reduce, corrosion potential and electrode reaction resistance increase.

Result of study confirm, the present embodiment by aniline to La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloy carries out surface modification, and do not change the structure of precursor alloy, modified alloy is still by LaNi ₅phase and La ₂ni ₇phase composition, not only improves AB ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20the chemical property of alloy electrode, also improves the kinetic property of electrode.

Claims (1)

1. one kind utilizes aniline surface modification AB ₃the method of type hydrogen storage alloy, is characterized in that concrete steps are:

(1) AB is prepared by vacuum induction melting method ₃type La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20precursor alloy, after alloy pig mechanical crushing, with rotating speed 250 ~ 300 revs/min of ball millings 60 ~ 90 minutes, sieves out 200 ~ 300 object La _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder;

(2) aniline, H is weighed ₂sO ₄be added to the water with ammonium persulfate, be mixed with solution, the aniline, 2 × 10 consisted of containing 0.25 mol/L of solution ^-3the H of mol/L ₂sO ₄with the ammonium persulfate of 0.25 mol/L;

(3) by La obtained for step (1) _0.94mg _0.06ni _3.49co _0.73mn _0.12al _0.20alloying pellet powder is put in the solution that step (2) prepares, magnetic agitation 10 minutes, washing, and suction filtration is dry, the obtained AB utilizing aniline surface modification ₃type hydrogen storage alloy.