Regulating Alkali Metal Deposition Behavior via Li/Na-philic Ni Nanoparticles Modified 3D Hierarchical Carbon Skeleton

Abstract Alkali metal anodes are promising anodes for constructing novel battery systems with high energy density. Nevertheless, limited nucleation sites and nonuniform local electric field caused dendrites growth and unlimited volume expansion hindered their practical implementation during electrochemical plating/stripping. Herein, a 3D N-doped carbon nanofiber skeleton wrapped with Ni nanoparticles encapsulated carbon nanotubes (CNTs-Ni@NCFs) is prepared by hydrothermal process and followed catalytic reaction under ethanol atmosphere to construct a superior Li/Na-philic host with stable chemical properties. The 3D NCF networks serve as a primary framework, providing sufficient voids for alkali metal deposition and rapid electron and ion transport. The Li/Na-philic Ni nanoparticles and catalyzed CNTs on CFs provide evenly distributed nucleation sites and uniform local electric field, leading to dendrite-free Li deposition, which is confirmed by theoretical calculations. Because of the guided deposition behavior and bare volume change, the CNTs-Ni@NCFs anode delivers an extremely low nucleation overpotential in the initial deposition and a superior plating/stripping voltage hysteresis under a high current density of 30 mA cm−2 for 300 cycles. The CNTs-Ni@NCFs-Li full cell with LiFePO4 cathodes demonstrates 94.2% capacity retention after 200 cycles under 2 C. When coupled with Na3V2(PO4)3 cathode, the CNTs-Ni@NCFs-Na cell shows a good suitability in full cell. This work shed new light on fabricating novel stable alkali metal anodes, which may also pave the way toward to other practical applications with high energy densities, such as in Li-air and Li-S batteries, etc.