全固态锂电池锂合金Li-M (M=Cu,Al,Sn)负极研究

All solid-state lithium batteries utilize solid state electrolytes to overcome the safety issues of the traditional organic liquid electrolyte, becoming one of the promoting candidate for electric vehicles and large-scale stationary-type distributed power sources. Nano-structured metal lithium materials are expected to be used directly in solid-state batteries, while taking advantage of the high energy density and safety, exert the inherent dynamics of nanomaterials, and achieve high energy and high power. However, the abnormal lithium dendrites growth, electrode/electrolyte solid interface impedance, poor interface stability, interfacial stress changes limit the application of lithium metal anodes during all solid-state lithium battery cycling, not only affect the cycle life and power performance, but also cause short circuit and other security problem. Based on these problems, the project intends to carry out all-solid lithium battery lithium alloy anode and interface research, through the nano-structured metal lithium anode, the surface modification protection, regulation of metal lithium local current density and deposition morphology, improve the lithium anode/solid electrolyte interface structure and interfacial compatibility, to achieve uniform deposition and dissolution of lithium. The new nanostructured solid metal lithium battery will improve the performance of all solid-state lithium batteries.

全固态锂电池采用固态电解质替代传统有机液态电解液，有望从根本上解决电池安全性问题，是电动汽车和规模化储能理想的化学电源之一。具有纳米结构金属锂材料有望直接在固态电池中获得应用，在兼具高能量密度和安全性的同时发挥出纳米材料固有的动力学优势，从而同时实现高能量和高功率。然而全固态锂电池在循环过程中金属锂会有枝晶产生，电极/电解质固固界面阻抗大、界面稳定性不良、界面应力变化等，不但影响循环寿命和倍率性能，更会造成短路等安全问题。针对这些问题，项目拟开展全固态锂电池锂合金负极研究，通过对金属锂负极材料纳米化，进行表面修饰保护，调控金属锂局部电流密度和沉积形态，改善锂负极/固体电解质的界面结构和界面相容性，实现锂的均匀沉积和溶解，开发新型纳米固态金属锂电池，提高全固态锂电池的性能。

基于金属锂作负极的全固态锂电池被认为是下一代理想的高能量密度电池体系，是电动汽车和规模化储能理想的化学电源之一。但是，金属锂负极在循环过程中由于不均匀沉积会产生锂枝晶，树突状锂枝晶可能会刺穿隔膜导致电池短路，而且在循环过程中易产生死锂，降低电池库仑效率。针对上述问题，一方面，采用全固态电解质替代有机液体电解液，提高电池的安全性能；另一方面，对金属锂负极进行改性，抑制锂枝晶的生成。项目开展了基于聚合物和无机材料的复合电解质、三维Cu@Sn纳米锥集流体、新颖复合隔膜制备等研究工作，抑制了锂枝晶的形成，改善了锂金属负极的库仑效率和循环稳定性。