Interfacially Redistributed charge for robust lithium metal anode

Highlights: • Interconnected Li₃P@Cu MCI was efficiently constructed on Li foil surface for interfacial charge redistribution. • Enhanced electrochemical Kinetics has been demonstrated by DFT calculations and symmetric cell. • Epitaxially growth of lithium was achieved within Li₃P@Cu interlayer. • Li₃P@Cu modified Li metal exhibited robust electrochemical performance over 1500 h. Li metal is the ultimate anode material for Li based battery with high energy density. However, inhomogeneous charge distribution from the unbalanced ion/electron transport is usually generated at the electrode surface, leading to the uncontrollable dendrites with poor reversibility. Herein, interconnected Li₃P@Cu ion/electron conductive interlayer activated from interfacial reaction between Cu₃P arrays and metallic Li is efficiently constructed on Li foil surface through room-temperature mechanical rolling process for charge redistribution. Demonstrated by theoretic calculation, the diffusion barrier of Li⁺ is remarkably reduced from Li₃P interphase with high ionic conductivity, while the electron-conductive Cu domains ensures well-dispersed current density, facilitating the uniform distribution of interfacial Li⁺ flux. Furthermore, the interconnected skeletons with extensive active channels significantly enhances the electrochemical kinetics and promotes the reversibility of Li plating/stripping processes. As expected, a prolonged lifespan of symmetrical cells over 1500 h with lower polarization is successfully achieved at 1 mA cm⁻², further improving the rates and cycling performances of LiFePO₄ based full cells in mass loading of 8.5 mg cm⁻² with a capacity retention up to 91.7% after 300 cycles. This work proposed a rational interlayer design for interfacial charge redistribution and presents an efficient strategy to realize dendrite-free Li metal anode.