Electroless Plating 3D Composite Current Collector for High-Performance Rechargeable Magnesium Batteries

Mg metal batteries offer a compelling solution to fulfill the critical demand for next-generation rechargeable batteries with a high energy density. Unfortunately, nonuniform Mg deposition shortens cycle life and poses safety risks. In this study, we present a three-dimensional (3D) current collector made of copper-coated carbon (Cu@CC), prepared by the electroless plating of copper particles onto the surface of the carbon cloth (CC) substrate. The Cu@CC composite structures are porous and magnesiophilic, which could effectively induce uniform deposition of Mg. The obtained 3D Cu@CC current collectors exhibit improved cycling performance, achieving long-term stability for more than 2000 cycles with an average Coulombic efficiency (CE) of 99.84%. Additionally, the Cu@CC composites enhance the compatibility between the Mg metal anode and the Celgard separator (5.92 mg cm^-2, 52% reduction in mass compared to glass fiber separators), achieving a high average CE of 99.35% for over 2000 cycles. Furthermore, the full cell constructed with a Mg-plated Cu@CC anode and a Mo₆S₈ cathode demonstrates exceptional cycling stability, retaining 97.2% of its capacity after 1200 cycles even under 200 mA g^-1. Particularly, the Mg@Cu@CC//Mo₆S₈ pouch cell exhibits excellent cycle stability of 300 cycles with 92.9% capacity retention. This work offers critical insights for advancing high-energy-density Mg metal batteries toward practical applications.