基于固有微孔聚合物的高性能锂金属负极保护膜的构造

Interfacial layer based on PIM for cathode of high-performance Li-metal battery

锂金属具备超高理论能量密度3860mA·h/g和最低的电极电位-3.04V等优点,受到了人们的广泛关注。但锂金属枝晶问题严重,极大地限制了锂电池的商业化进程。基于固有微孔聚合物DMBP-TB(其中DMBP为二甲基联苯,聚合物属于Troger′s base TB聚合物,故命名为DMBP-TB)为负极保护膜,可实现对金属锂的高效保护以及高库仑效率的长循环。DMBP-TB聚合物一方面可为锂离子沉积提供通道,另一方面可缓冲锂金属充放电过程中体积变化带来的应力变化。采用固有微孔聚合物包覆,可在面电流密度高达2mA/cm^2时高效循环150周。该多孔聚合物拥有良好的成膜特性,因而可用简便的旋涂法实现大面积的制备,便于金属锂负极进一步实现商业化。

Li metal is the ultimate choice for the cathode in a Li battery because it has the highest theoretical capacity(3860mA·h/g)and lowest electrochemical potential(-3.04V).A novel class of solution processable polymers with intrinsic pores,known as“polymer with intrinsic microporosity”(PIM)was used to prevent lithium dendrite formation.The PIM(specifically DMBP-TB)based protective interfacial layer can provide effective conducting pathways for Li ions.On the other hand,The DMBP-TB artificial layer was strong enough to sustain the pressure induced by Li dendrite.Thus,with this PIM protecting,an excellent cyclability can be maintained at 2mA/cm2 for more than 150cycles.In addition,this type of microporous polymer shown excellent film-forming properties,which will enable the practical mass production by spin-coating methods.