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What are the advantages of lithium titanate as lithium battery anode material

wallpapers Tech 2021-01-08
Spinel-type lithium titanate is used as a kind of negative electrode material that has attracted much attention because it has the following advantages:
 
1) Lithium titanate has almost "zero strain before and after lithium deintercalation (the unit cell parameters before and after deintercalation" a changed from 0.836nm to 0.837nm only);
 
2) The lithium intercalation potential is high (1.55V) to avoid the generation of "lithium dendrites", and the safety is high;
 
3) Have a very flat voltage platform;
 
4) High chemical diffusion coefficient and Coulomb efficiency.
 
The many advantages of lithium titanate determine its excellent cycle performance and high safety. However, its conductivity is not high, and its capacity decays severely during high current charging and discharging. Surface modification or doping is usually used to improve its conductivity. rate.
 
For example, Xiao et al. used Mg(NO3)2 as the magnesium source to prepare Mg2+-doped lithium titanate by solid-phase method, indicating that doping Mg2+ did not destroy the spinel crystal structure of lithium titanate, and the material after doping It has better dispersibility. Its specific capacity can reach 83.8mAh/g at a discharge rate of 10C, which is 2.2 times that of undoped materials, and there is no significant decrease in capacity after 10 cycles of charge and discharge. The AC impedance test shows that The charge transfer resistance of the doped material is significantly reduced. Zheng et al. prepared pure-phase lithium titanate and carbon-coated lithium titanate using Li2CO3 and lithium citrate as the lithium source by high-temperature solid-phase method, respectively.
 
Experiments have shown that carbon-coated lithium titanate has a smaller particle size and good dispersibility, and exhibits better electrochemical performance. This is mainly due to the carbon coating that improves the electronic conductivity of the lithium titanate particle surface At the same time, the smaller particle size shortens the diffusion path of Li+.

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