Transition metal phosphate-clad composite lithium ion battery anode material

Abstract

The invention discloses a transition metal phosphate-clad composite lithium ion battery anode material with lithium-storing active material as a main core and electrochemically active transition metal phosphate as a cladding layer. The active material core mainly carries out electrochemical reaction, and provides battery capacity; and the cladding layer not only can protect the lithium-storing active material and reduce the dissolution and erosion of the active material by electrolyte, but also can increase the battery capacity and improve the rate capability of the active material.

Description

technical field [0001] The invention belongs to the technical fields of electrochemistry, material chemistry and chemical power supply products, and in particular relates to a lithium-ion battery composite cathode material Background technique [0002] Energy is the basic support of the national economy and one of the five elements for human survival. Energy security directly affects national security, sustainable development and social stability, and mineral energy provides 90% of the world's energy. According to scientific calculations, the proven reserves of oil, coal, and natural gas are 140 billion tons, 1,031.6 billion tons, and 152m 3 According to the current mining level, they can still be mined for 30 years, 200 years, and 60 years. The depletion of fossil energy resources urgently requires the development of new renewable energy and efficient clean energy. Lithium-ion batteries have attracted widespread attention because of their high operating voltage, high ener...

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Problems solved by technology

[0004] The cathode material that has been commercialized at this stage is LiCoO 2 , due to the lack of cobalt resources, toxicity and unsafety, it is not suitable for electric vehicle batteries

Because Ni 3+ Unstable, difficult to prepare stoichiometric LiNiO 2

Spinel LiMn 2 o 4 Due to the electrolyte decomposition at high charge potential, the Jahn-Teller effect at low discharge potential, and the easy dissolution of manganese ions in the electrolyte, its cycle performance is poor, which hinders its large-scale commercial application.

The lithium-rich composite material nLi 2 MnO 3 .(1-n)LiMO 2 Li in (02 MnO 3 It is an insulator, which leads to poor cycle performance, poor rate performance, and low coulombic efficiency for the first charge and discharge.

People use Mg, Al, Ti, V, Cr, Co, Ni and other metal ions to do modification research, but the effect is not ideal

In addition, Al, which is not easy to dissolve and has a stable structure, is widely used. 2 o 3 , MgO, SiO 2 Surface treatment and coating of other oxides can improve the cycle performance, but because these oxides are not electrochemically active, the specific capacity is lost, and the lithium ion transport channel is hindered, which affects the rate performance.

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