Guided lithium nucleation and growth on lithiophilic tin-decorated copper substrate

Abstract

Lithium metal is the ultimate anode choice for high energy rechargeable lithium batteries owing to its ultra-high theoretical capacity, however, Li dendrites and low Coulombic efficiency (CE) caused by disordered Li plating restrict its practical application. Herein, we develop an ultrathin Sn-decorated Cu substrate (Sn@Cu) fabricated by an electroless plating method to induce ordered Li nucleation and growth behavior. The lithiophilic Sn interfacial layer is found to play a critical role to lower the Li nucleation over-potential and promote fast Li-migration kinetics, and the underlying mechanism is revealed using the first principle calculations. Accordingly, a dense dendrite-free and Li deposition with large granular morphology is obtained, which significantly improved the CE and cycling performance of Li||Sn@Cu half cells symmetric cells. Symmetric cells using the Li-Sn@Cu electrode display a much-prolonged life span (>1200 h) with low overpotential (∼18 mV) at a high current density of 1 mA cm−2. Moreover, full cells paired with commercial LiFePO4 cathode (1.8 mAh cm−2) deliver enhanced cycling stability (0.5 C, 300 cycles) and excellent rate performance. This work provides a simple and effective way to bring about high efficiency and long lifespan substrates for practical applications.