A kind of preparation method of quasi-single crystal high nickel multicomponent material

Abstract

The invention provides a method for preparing a kind of single-crystal high-nickel multi-component material, which is characterized in that it comprises the following steps: preparing a quasi-single-crystal high-nickel positive electrode precursor: adding additive A to the reaction kettle bottom liquid in a nitrogen protective atmosphere; A mixed solution of nickel-cobalt-manganese ternary salt solution and additive B is added into the reactor, wherein the molar ratio of Ni, Co, and Mn in the nickel-cobalt-manganese ternary salt solution is 1-a-b:a:b, 1>1 ‑a‑b≥0.6, 0.4≥a≥0, 1≥b>0, the mass ratio of nickel-cobalt-manganese ternary salt solution to additive B is 1:(0.01%‑0.1%), controlled by alkaline solution containing ammonia pH value for co-precipitation reaction. The preparation method of the quasi-single-crystal type high-nickel multi-element material of the present invention prepares a kind of quasi-single-crystal high-nickel multi-element material that can be formed by roasting at low temperature. surface nickel content.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and in particular relates to a method for preparing a quasi-single-crystal high-nickel multi-element material. Background technique [0002] Nickel-cobalt lithium manganese oxide multi-component positive electrode material (hereinafter referred to as multi-component positive electrode material) is a new type of high-capacity lithium-ion battery positive electrode material. Generally, nickel is the main electrochemically active material in the multi-component material, and cobalt can reduce the electrochemical polarization of the material and improve Manganese can improve structural stability and thermal stability, so the synergistic effect of two or three elements in nickel-cobalt-manganese makes the multi-element positive electrode material have good structural stability and comprehensive electrochemical performance, in terms of safety performance, cycle performance and It has certain advant...

AI Technical Summary

Problems solved by technology

[0003] However, there are still some problems with the high-nickel multi-component material used as the positive electrode material of the power battery: (1) The material is mostly a secondary agglomerated ball, and its internal and external primary particle sizes are small and have many structural defects. (2) The internal pores of the multi-element positive electrode material are large, the volumetric energy density is low, and the internal particles are difficult to cover. During the charge-discharge cycle, the electrolyte gradually soaks into the porous positive electrode material and interface with the electrolyte occurs. reaction, resulting in the destruction of the material structure and the serious dissolution of metal cations, which eventually leads to the degradation of cycle (especially high temperature cycle) performance and safety performance

(3) The secondary agglomeration structure of the multi-component positive electrode material is easily crushed during the preparation of the positive electrode sheet of the battery, resulting in the exposure of the internal particles of the material, the intensification of interface side reactions and the dissolution of metal ions, and the large capacity of the battery during high-temperature cycling. attenuation

However, due to the high calcination temperature used in this method, the high temperature will seriously damage the high-capacity characteristics of high-nickel materials and cannot be applied to high-nickel materials.

[0005] At the same time, due to the nickel-rich multi-component material, there are more residual lithium salts on the surface after roasting, which has a higher pH value and continues to absorb water, which has a greater impact on the homogenization process

Most manufacturers reduce the lithium salt on the surface of high-nickel materials by means of water washing or pickling, but studies have shown that water washing will reduce the cycle stability and rate performance of high-nickel materials, which is very important for positive electrodes such as power batteries that have high requirements for life and power performance. The material is difficult to be practical

At the same time, coating and multiple firings after washing will increase additional costs

Images