Preparation method of nickel sulfate coated ferriferrous oxide particle for iron-nickel battery

Abstract

The invention discloses a preparation method of a nickel sulfate coated ferriferrous oxide particle for an iron-nickel battery, and belongs to the technical field of iron-nickel battery electrode materials. The preparation method comprises the following steps: synthesizing nickel alkyl xanthate from alkyl xanthate and a water-soluble nickel salt according to a molar ratio of 2:1, dissolving the nickel alkyl xanthate in a pyridine solution to obtain a pyridine solution of the nickel alkyl xanthate, uniformly mixing the pyridine solution of the nickel alkyl xanthate with ferriferrous oxide powder, and keeping the temperature at 300-400 DEG C for 20-60 min to obtain the target product. The coating layer of the nickel sulfate coated ferriferrous oxide particle prepared in the invention is uniform and compact, the particle size of a micron-sized ferriferrous oxide particle is reduced into micro-nano or less, the surface of the particle trends to a spheroidic shape, and the nickel sulfate coated ferriferrous oxide particle p can effectively improve the activation rate, the charging efficiency, the discharge capacity, the rate performances and the cycle performances of an iron negative electrode.

Description

technical field [0001] The invention belongs to the technical field of electrode materials for iron-nickel batteries, and in particular relates to a preparation method for nickel sulfide-coated ferric oxide particles for iron-nickel batteries. Background technique [0002] In recent years, as people's awareness of environmental protection has increased, clean energy such as solar energy and wind energy, as well as electric vehicles, have developed rapidly. Therefore, as a battery system for energy storage and electric vehicles, it is urgent to develop a battery system with stable performance, long cycle life, high safety performance, low price and environmental friendliness. In recent years, iron-nickel batteries have re-entered people's field of vision and attracted great attention. Iron-nickel batteries were invented by Edison in 1900. They are characterized by long cycle life, high safety, low price and environmental protection. For locomotive traction power. However, t...

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Problems solved by technology

Common beneficial additives are FeS, PbS, Bi 2 S 3 、Na 2 S and K 2 S and other sulfides and NiSO 4 or Ni(OH) 2 etc., the addition of these additives inhibits the passivation of the iron electrode to a certain extent and improves the capacity of the iron electrode, but the electrochemical performance of the iron battery cannot be improved to the greatest extent due to the simple addition of these additives

Recently, Wang et al reported in Electrochimica Acta 231 (2017) 479-486 a method of chemical oxidation precipitation to synthesize Fe 3 o 4 @NiS nanocomposite, the specific steps are to generate Fe by reacting with ferrous sulfate, hydrogen peroxide and sodium hydroxide 3 o 4 nanoparticles, and then adding thiourea and nickel chloride, the resulting NiS fine particles are deposited on the Fe 3 o 4 On the particle surface, experiments have shown that deposition of 5wt% NiS on Fe 3 o 4 Under the condition of low rate 0.15C discharge, the discharge capacity of the particles can reach up to 507mAh / g, but under the condition of 1.5C high rate, the discharge capacity can only reach 109mAh / g, 10wt% NiS Fe 3 o 4 The discharge capacity of the particles can only reach 352mAh / g at 1.5C, but the discharge capacity is significantly reduced at low magnification

The main disadvantage of this method is that the fine particles of NiS generated by chemical reactions are naturally deposited on Fe. 3 o 4 It is difficult to obtain a uniform and dense coating layer on the surface of the particles. Therefore, the improvement of its electrochemical performance is limited. To improve the high-rate performance, it is necessary to increase the deposition amount of nickel sulfide to more than 10wt%.

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