Suppression of potassium dendrite via surface control of substrate

With its abundance and low redox potential, potassium (K) is considered as the most promising anode material for next-generation rechargeable batteries. However, due to the highly reactive nature of K in the electrolyte, irregular electrodeposition of K leads to continuous dendrite growth, resulting in poor electrochemical performances. Herein, structurally and chemically defected crumpled graphene (d-CG) is used as the host material to suppress dendrite growth and reduce overpotential. The defects on d-CG are highly potassiophilic which homogenize K ion flux and local current density. As a result, d-CG represents a dendrite-free morphology during K plating/stripping and high electrochemical performance. d-CG shows high coulombic efficiency (CE) while copper foil exhibits lower CE. In addition, in a half cell (K||d-CG), d-CG electrode represents significantly lower overpotential at 110mV than that of K (160mV). By virtue of defect effects on dendrite control, stable K metal batteries are realized. This study provides a step forward for K metal batteries.