Improved Cycling Stability of Lithium-Metal Anode with Concentrated Electrolytes Based on Lithium (Fluorosulfonyl)(trifluoromethanesulfonyl)imide

A new type of concentrated electrolyte composed of Li[(FSO2)N(SO2CF3)] (LiFTFSI), Li[N(SO2F)(2)] (LiFSI), and ether solvents can improve the cycling stability of lithium (Li) metal and inhibit Li-metal dendritic growth. The high average coulombic efficiency of >95% and excellent cycling performance of >250 cycles for the Li vertical bar copper cells have been achieved, even at a high current density of 3 mA cm(-2). Moreover, the Li vertical bar LiFePO4 cell exhibits superior cycling stability with capacity retention of >92% at 0.2 C for more than 200 cycles and excellent C-rate capability.