Copper and barium activated lithium iron phosphate cathode material

Abstract

The invention discloses a copper and barium activated lithium iron phosphate cathode material. The chemical general formula of the material is LiCuxBayFePO4, wherein x is between 0.00002 and 0.00005; Y is between 0.0003 and 0.003; and the molar ratio of Li to Cu to Ba to Fe to P is 1:0.00002-0.00005:0.0003-0.003:1:1. A small amount of substitutional copper and a small amount of barium are doped, so the control of the morphology and particle size of a product is facilitated to obtain a stable lithium iron phosphate compound; crystal lattices of the material are activated, the lithium ion diffusion coefficient is improved, and the first discharge capacity of the material is 160.52mAh / g; the relative lithium electrode potential of a charge and discharge plateau of the material is about 3.5V, the initial discharge capacity exceeds 168mAh / g, and the capacity is attenuated by about 1.2 percent after charge and discharge cycle for 100 times; and compared with an undoped LiFePO4 contrast embodiment, the invention has the advantages that: the specific capacity and cycle stability are greatly improved.

Description

technical field [0001] The copper and barium activated lithium iron phosphate positive electrode material of the invention belongs to a lithium battery positive electrode material, in particular to a lithium iron phosphate battery positive electrode material. Background technique [0002] At present, the research status of lithium iron phosphate doping modification: lithium iron phosphate LiFePO4 is non-toxic, environmentally friendly, high in safety, rich in raw materials, high in specific capacity, stable in cycle performance, and low in price. The stable discharge platform with a theoretical capacity of 3.5V, the lithium iron phosphate material has high energy density, low price, and excellent safety, and is especially suitable for power batteries. But it has a higher resistivity. Due to lithium iron phosphate, the kinetics of LiFePO4 is not good at room temperature, and the rate performance is extremely poor. Researchers at home and abroad have used methods such as coat...

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Problems solved by technology

[0005] At present, there is a consensus that lithium iron phosphate has the advantages of good safety, no pollution, stable cycle performance, high specific capacity and low price, but it also has poor conductivity and the disadvantage of lower tap density