Extending the Low-Temperature Operation of Lithium-Metal Batteries Combining LiNO₃-Based Eutectic Additive and 3D Lithium-Metal Anode

For Li-metal batteries (LMBs), a decrease in operating temperature leads to sluggish kinetics and reduced ionic conductivity of the carbonate electrolyte. Combined with severe Li dendrites, the electrochemical performance largely deteriorates. To solve these problems, the combined effects of LiNO3-based eutectic additive and 3D Li-metal anode are investigated in carbonate electrolyte-based LMBs. Results show that the best-performing full cells take advantage of both approaches simultaneously by using BE-0.5% electrolyte with the 3D-Ni@Li anode for high-performance LMBs. The 3D-Ni@Li|BE-0.5%|LiFePO4 cell can achieve a long lifespan up to 800 cycles at 1C with 96.5% capacity retention. The NCM622 cell also displays a capacity retention of 85.9% after 200 cycles and a good low-temperature suitability with carbonate electrolyte (>69% capacity retention) at −40 °C. The good performance of LMBs can be attributed to two advantages: (a) the LiNO3-based eutectic additive can regulate SEI components for reaction kinetics enhancement and (b) 3D-Ni@Li can realize minimum volume change and provide a stable framework to enable a robust SEI layer. This work provides novel insights into individual and combined design approaches for fabricating LMBs with long-term stability and low-temperature operation.