Alloy-Type Lithium Anode Prepared by Laser Microcladding and Dealloying for Improved Cycling/Rate Performance.

Abstract

Nanosized alloy-type materials (Si, Ge, Sn, etc.) present superior electrochemical performance in rechargeable batteries. However, they fail to guarantee cycling capacity and stability under high mass loading required by industrial applications due to low electric contact and adhesive strength, which has long been a challenge. This work proposes a rational design for an alloy-type anode via facile and versatile laser microcladding and dealloying. The proposed anode features a large-area porous network composed of continuous nano-ligaments, which consist of evenly distributed nanosized alloy-type material metallurgically bonded with conductive material. The fabrication of the structure is validated using Ge-Cu and Sn-Cu anodes, both exhibiting enhanced cycling stability at high areal capacity and rate performance in lithium-ion batteries. The enhancement is attributed to the structural features, which contribute to lithiation-delithiation stability and intact electron/Li ion transference path, as verified by in situ and ex situ transmission electron microscopy observations. More importantly, the critical solidification conditions of laser microcladding are provided by a multiphysics simulation, allowing for a thorough understanding of the structural formation mechanism. The study provides a possible approach to improve mass loading and performance of an alloy-type anode for practical application.