Li-Indium alloy anode for high-performance Li-metal batteries

Lithium metal has been considered one of the most ideal anode materials for batteries due to its ultrahigh theoretical capacity and energy density. However, the unstable SEI layer and the growth of Li dendrites cause poor cycling performance and even safety hazards, which also severely restrict the commercial application of Li metal batteries. In this paper, a Li-In alloy anode was designed and prepared by mechanical rolling of both Li and In pure metal foils together. Three-dimensional Li-In alloy network structures are formed by mechanical alloying during rolling, and the 3D Li-In alloy structure not only possesses strong lithium affinity but also possesses more interface between the Li matrix and the second phase formed in mechanical alloying, which can promote rapid diffusion at the interface and uniform deposition of lithium ions. As a result, the Li-In electrode shows an extremely low overpotential of approximately 35 mV at a high current density of 5 mA cm−2 during the lithium plating/stripping experiment. In addition, the battery revealed a higher discharge capacity of 295 mAh/g at 0.05 C and capacity retention of 80 % after 150 cycles when the Li-In alloy was used as the anode electrode in a cell with Li1.2Ni0.2Mn0.6O2 as the cathode. The Li-In alloy can also be used as anode of Li-S battery, the result showed that the capacity decay rate was reduced from 0.22 % to 0.1 % after 200 cycles without any decoration treatment of S cathode except conductive carbon. This work verified that indium in the Li-In alloy can effectively protect the lithium anode and provides an idea for the practical application of lithium metal batteries.