Mo_(2)C催化的低压纳米Li_(2)C_(2)O_(4)预锂化用于高能量锂离子电池  

Mo_(2)C catalyzed low-voltage prelithiation using nano-Li_(2)C_(2)O_(4) for high-energy lithium-ion batteries

作　　者：钟伟 张策 李思吾 张薇 曾子琪 程时杰 谢佳 Wei Zhong;Ce Zhang;Siwu Li;Wei Zhang;Ziqi Zeng;Shijie Cheng;Jia Xie(State Key Laboratory of Advanced Electromagnetic Engineering and Technology,School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430000,China;State Key Laboratory of Materials Processing and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]State Key Laboratory of Advanced Electromagnetic Engineering and Technology,School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430000,China [2]State Key Laboratory of Materials Processing and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China

出　　处：《Science China Materials》2023年第3期903-912,共10页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China (U1966214 and 22008082).

摘　　要：初始循环中不可逆的锂损失显著降低了锂离子电池的能量密度预锂化是补偿锂损失的有效方法之一,但目前的方法存在预锂化试剂不稳定或容量低的问题.草酸锂(Li_(2)C_(2)O_(4))作为一种高理论容量(相当于锂金属)、低成本和空气稳定的锂补偿材料已显示出巨大的潜力.然而低电化学活性和高分解电位严重阻碍了其实际应用.本文中,我们报道了一种低压预锂化技术.通过配合使用Mo_(2)C催化剂和纳米Li_(2)C_(2)O_(4)Mo_(2)C催化剂改变了Li_(2)C_(2)O_(4)周围的电子云分布,大大降低了活化能,从而显著加速了锂从Li_(2)C_(2)O_(4)中的释放.通过冷冻干燥制备的纳米Li_(2)C_(2)O_(4)与Mo_(2)C催化剂形成良好接触并展现出快速的离子和电子传导.得益于这种协同效应,Li_(2)C_(2)O_(4)的分解电位降低了0.5 V,分解效率接近100%.纳米Li_(2)C_(2)O_(4)/Mo_(2)C复合材料补偿的LiCoO_(2)||SiO全电池展现出可以高于对照组46.9%的比容量,显示出巨大的实际应用潜力.Irreversible lithium loss in the initial cycles appreciably reduces the energy density of lithium-ion batteries.Prelithiation is an effective way to compensate for such lithium loss,but current methods suffer from either the instability or low capacity of prelithiation reagents.Lithium oxalate (Li_(2)C_(2)O_(4)) has shown great potential as a lithiumcompensation material because of its high theoretical capacity(equivalent to lithium metal),low cost,and air stability However,the practical applications of Li_(2)C_(2)O_(4)are limited by its low electrochemical activity and high critical decomposition voltage.In this study,we performed the prelithiation of a low-voltage cathode by using Mo_(2)C catalysis and nanoLi_(2)C_(2)O_(4).Results show that the Mo_(2)C catalyst changes the electron cloud distribution around Li_(2)C_(2)O_(4)and greatly reduces the activation energy,thereby significantly accelerating the lithium release from Li_(2)C_(2)O_(4).The nano-Li_(2)C_(2)O_(4)prepared by freeze-drying shows accelerated ionic and electronic conduction as well as close contact with Mo_(2)C.Benefiting from the synergistic effect,the decomposition potential of Li_(2)C_(2)O_(4)is decreased by 0.5 V with an efficiency close to 100%.The LiCoO_(2)||SiO full cell empowered with the nano-Li_(2)C_(2)O_(4)/Mo_(2)C prelithiation composite demonstrates 46.9%higher capacity than the control and thus has great potential for practical applications.

关 键 词：锂离子电池 理论容量 预锂化 电化学活性 分解电位 全电池 电子传导 能量密度 

分 类 号：TM912[电气工程—电力电子与电力传动] TQ131.11[化学工程—无机化工] TB383.1[一般工业技术—材料科学与工程]