Tailoring solvation chemistry by hydrogen bonds in carbonate electrolytes for highly stable lithium-metal batteries

Abstract

The application of carbonate electrolytes in lithium-metal batteries (LMBs) has been impeded by low Coulombic efficiency, Li dendrite growth, and an unstable solid electrolyte interphase (SEI). Herein, a facile method is proposed to tailor solvation chemistry in carbonate electrolytes via hydrogen bonds for highly stable LMBs. The inexpensive and eco-friendly urea is used as an additive to promote LiNO₃ dissolution and inhibit HF generation in LiPF₆-based carbonate electrolytes. LiNO₃ facilitates the formation of an N-enriched stable SEI and suppresses the Li dendrite growth, hence improving the compatibility of carbonate electrolytes with Li-metal anodes. The suppression effect on HF generation significantly improves the stability of Ni-rich LiNi_0.8Co_0.1Mn_0.1O₂ at both room and elevated temperatures. Benefiting from urea and LiNO₃, the designed electrolyte enables a 4.25 V Li‖NCM811 (50 μm thin Li-metal anode and 1.7 mA h cm⁻²) cell to exhibit excellent cycling stability over 480 cycles with a capacity retention of 70.8% at 0.5C. This work introduces an efficient approach to simultaneously improve the stability of Li-metal anodes, NCM811 cathodes, and LiPF₆-based carbonate electrolytes, opening a new avenue for advanced electrolyte design.