Forming Solid-Electrolyte Interphases with Rich Grain Boundaries on 3D Lithiophilic Skeleton for Low-Temperature Lithium Metal Batteries

Rational design of the current collector along with further constructing solid electrolyte interphases (SEI) shows great promise to achieve uniform lithium (Li) deposition, specifically at low temperature. Here we report a Li2O-Ni based SEI layer with rich grain boundaries formed on the three-dimensional (3D) Ni-NiO current collector for stabilizing Li metal anodes. Different from two-dimensional (2D) substrates, the lithiophilic 3D substrates with porous structures exhibit high binding affinity to Li and provide enough space for volume fluctuation, leading to uniform Li deposition. The grain boundaries between Li2O (111) and Ni (111) in the SEI layer display a low diffusion barrier of Li+, facilitating Li+ transport through the interface. As a result, Li||NCM811 full cells using 3D Ni-NiO display an excellent cycling stability with capacity retention of 80.8% after 160 cycles under harsh conditions, i.e., a limited Li supply (N/P = 2.4) and a high areal capacity (4.0 mAh cm−2). Even at low temperature of -30°C, Li||NCM811 full cells with 3D Ni-NiO exhibit a large areal capacity of 3.2 mAh cm−2 and apparently enhanced cycle life with limited Li anode (N/P = 1.2) compared with non-lithiophilic 3D current collectors.