Lithiophilic and conductive framework of 2D MoN nanosheets enabling planar lithium plating for dendrite-free and minimum-volume-change lithium metal anodes

Abstract

Lithium (Li) is a promising anode for high-energy rechargeable batteries but its practical implementation is impeded by uncontrollable dendrite growth and huge volume changes. Herein, we report a dendrite-free Li composite anode with minimum volume change, which is composed of 3D interpenetrating Li and lithiophilic MoN nanosheets prepared by mechanical rolling and folding. The conductive 2D MoN nanosheets boasting excellent lithiophilic affinity and small lattice mismatch with Li induce planar Li plating therefore suppressing dendrite growth along the perpendicular direction. The MoN nanosheets interwoven framwork provides abundant Li accommodation sites and the horizontally plated Li fills the nanoscale gaps between the MoN nanosheets, thus minimizing volume change during cycling. Li3N generated in situ by the surface reaction between MoN and Li enhances the ionic conductivity and interface stability. The Li-MoN anode shows a low Li plating overpotential of 15.0 mV and excellent stability for 2,500 h at 1 mA cm−2. Paired with the LiFePO4 cathode, the full cell shows 99.7 % Coulombic efficiency and 87.7 % capacity retention after 650 cycles at 170 mA g−1. The results provide insights into the design of 3D host enabling planar Li plating for dendrite-free and minimum-volume-change Li metal anodes.