Micrometer-sized 3D porous structure decorated with uniform InSb alloy layer towards dendrite-free Li metal electrode

Abstract

Li metal electrode is expected to be one promising anode to construct high energy density batteries because of its high theoretical specific capacity and the lowest electrode potential. However, uncontrollable dendrite growth and large volume changes cause batteries failure and safety risks. Here, an InSb alloy modified three-dimensional porous Cu (3D Cu@InSb) is constructed by electroless plating coupled with electroplating to stabilize the Li metal electrode. The suitable 3D porous structure with pore size of several micrometers can provide uniform current distribution, rapid ionic transferring channels, and effectively accommodate volumetric changes and release stress as well, avoiding the limited modifying effect using too large pores and poor ionic transport kinetics using too small pores. Moreover, the InSb alloy modified layer with high binding energy to Li+ reduces the nucleation overpotential and enhances the Li plating/stripping reversibility. Under the synergistic effects of InSb alloy modified layer and suitable 3D porous structure, Li metal is uniformly plated/stripped in pores with almost thorough flat surface even under a high area capacity of 4 mAh cm−2. The full battery assembled using LiFePO4 (LFP) cathode demonstrates a long life of 600 cycles at 2 C with a capacity retention of 86 %.