A kind of positive electrode material and its preparation method and application

Abstract

The invention provides a positive electrode material and a preparation method and application thereof. The positive electrode material is α-NaFeO 2 structure, the general chemical formula of the cathode material is Li x co 1‑y Al z M1 m M2 n o 2 , wherein, M1 is Ni and / or Mn, M2 is any one or a combination of at least two of Mg, Ti, Y, La, Zr, B, Nb, W, Sr, F, P or Ce, 0.98<x <1.04, 0<y<0.06, 0.005<z<0.05, 0.001≤m<0.02, 0<n<0.05. The invention combines multi-element, multi-point, uniform and appropriate doping of the positive electrode material, and can significantly improve the energy density, power density and fast charging of the battery under high working voltage under the premise of ensuring the safety of the battery. characteristics, improving the high-temperature storage, high-temperature floating charge, low-temperature discharge and high-temperature cycle characteristics of the battery.

Description

technical field [0001] The invention belongs to the technical field of lithium secondary batteries, and relates to a positive electrode material and a preparation method and application thereof. Background technique [0002] Secondary batteries (such as lithium-ion batteries) are widely used in today's society, such as mobile phones, notebooks, tablet computers, electric vehicles, electric bicycles, electric buses, industrial and household energy storage, aerospace, etc. Different application scenarios have different requirements for the various indicators of the battery, but in general, it is hoped that the battery can take into account specific energy, energy density, fast charging, power density, low-temperature discharge, and high-temperature storage under the premise of ensuring safety. , high temperature cycle, floating charge, intermittent cycle, pulse discharge, low cost, environmental protection and other indicators. [0003] At present, commercialized lithium-ion ...

AI Technical Summary

Problems solved by technology

Currently pure lithium cobalt oxide Li 1-x COO 2 When the delithiation amount x≥0.5 of the material (that is, the charging cut-off voltage is greater than 4.20V), the cycle life, especially the cycle life at high temperature 45°C, begins to decline significantly, and it is difficult to support a cycle life of more than 500 times, which cannot meet the actual application requirements

[0006] CN101945825A discloses a cobalt oxyhydroxide and a lithium cobaltate positive electrode prepared therefrom. In the literature, there is no research on the improvement of the structural stability of the lithium cobaltate positive electrode material and no effective design ideas, which cannot solve the problem of high cut-off voltage conditions. structural stability issues

CN103199242A discloses a borosilicate-coated and modified lithium cobaltate and its preparation method. This method cannot solve the problem of the bulk phase structure stability of lithium cobaltate under the condition of high charge state, and cannot be applied to the situation of high cut-off voltage

CN103618080A discloses a pretreatment method for preparing high-voltage lithium cobaltate with tricobalt tetroxide. The method coats a layer of Ti-containing compound on the surface of tricobalt tetraoxide. The technology disclosed in this method only involves the use voltage range of 2.8~4.35V for lithium cobaltate ;Unable to further increase the upper limit voltage of lithium cobalt oxide (such as 4.50V, 4.53V, etc.) under the condition of ensuring safety and cycle life

CN104037407A discloses a lithium cobalt oxide composite material coated with a lithium superionic conductor and a preparation method thereof, mainly including LMTMP 3 o 12 compound, because the coating cannot solve the stability problem of the bulk phase structure under the condition of high upper limit voltage, so this technology cannot solve the problem of high voltage lithium cobalt oxide cycle life attenuation

CN104953096A discloses a surface-modified high-voltage lithium cobaltate positive electrode material and its preparation method. In this document, acid treatment is used, which is difficult for industrial application. In addition, it cannot solve the problem of material structure stability under the condition of high delithiation state

While the coating improves the stability of the interface between the powder material and the electrolyte, it leads to a significant decrease in the discharge specific capacity and an increase in impedance

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