Suppressing Lithium Dendrite Growth via Sinusoidal Ripple Current Produced by Triboelectric Nanogenerators

摘要

Lithium metal as an ultimate anode material of future rechargeable batteries may furnish the highest energy density for its pairing cathode, although preventing the growth of lithium dendrites in liquid electrolytes is a major challenge. This work reports that stable lithium metal anodes can be achieved by charging with high-frequency sinusoidal ripple current generated by rotating triboelectric nanogenerators (R-TENGs). Compared with constant DC current charging, sinusoidal ripple current charging by R-TENG improves the uniformity of lithium deposition during cycling test. Consequently, symmetric Li/Li cells exhibit lower overpotential and better cycling stability. In addition, full cells assembled with lithium metal anodes and LiFePO4 cathodes show considerably improved capacity retention when charged by R-TENG's sinusoidal ripple current (99.5%) compared to constant current (78.7%) after 200 cycles. The charging strategy device in this work provides a promising direction toward improving the cycle life of Li metal batteries. In addition, the combination of R-TENGs with Li metal batteries offers an encouraging solution for achieving stable energy supply in self-powered systems.