Evaluating the feasibility of copper-based skeletons in lithium metal batteries operated at subzero temperature

Abstract

The next-generation lithium (Li) metal batteries suffer severe low-temperature capacity degradation, appealing for expeditions on solutions. Herein, the feasibility of copper-based skeletons (i.e., 2D Cu foil, 3D Cu mesh, and CuZn mesh) frequently adopted in the stabilization of Li are evaluated at low temperatures. Li growth patterns and stripping behaviors on different skeletons and at different temperatures uncover the dendrite-free and dead-Li-less Li deposition/dissolution on CuZn mesh. Three-electrode impedance indicates the dynamic advantages of CuZn mesh, driving fast Li⁺ crossing through solid-electrolyte-interphase and charge transfer process. Notably, CuZn mesh enables the stable operation and fast charging (1.8 mA cm⁻²) of Li || LiFePO₄ cells for over 120 cycles at −10 °C with a superior capacity retention of 88%. The success of CuZn mesh can be translated into lower temperature (−20 ^oC) and 1.0-Ah-level pouch cells. This work provides fundamentals on improving low-temperature battery performances by skeletons with regulated spatial structure and lithiophilicity.