2D MXene Anodes with Engineered Electrolyte for High-Performing Lithium-Ion Batteries in Extreme Cold

Lithium-ion batteries (LIBs), while widely adopted, suffer from severe performance losses at subzero temperatures due to sluggish Li⁺ ion diffusion, increased interfacial resistance, and electrolyte freezing. In this study, the use of titanium carbide (Ti₃C₂T_x) MXene is investigated as an anode material to overcome these limitations with high electrical conductivity, large interlayer spacing, and pseudocapacitive charge storage enabling efficient lithium-ion transport even at low temperatures. Electrochemical characterization demonstrates that Ti₃C₂T_x MXene electrodes provide significantly lower charge-transfer resistance and superior low-temperature performance than graphite, delivering 31.7 mAh g^-1 at -70 °C (C/30 rate) while graphite exhibits negligible capacity even at -50 °C. These performance enhancements are enabled by the pseudocapacitive behavior of Ti₃C₂T_x MXene and its surface terminations, which facilitate rapid lithium-ion transport-a mechanism confirmed by density functional theory (DFT) calculations. The combination of Ti₃C₂T_x MXene electrodes and dipropyl ether (DPE)-based lithium bis(fluorosulfonyl)imide (LiFSI) electrolyte-which retains ≈67% of its room-temperature ionic conductivity at -10 °C-enables stable electrochemical performance in extreme cold, surpassing the operational limits of conventional lithium-ion batteries. To the best of this knowledge, this is the first report of functional lithium-ion battery operation down to -70 °C using a Ti₃C₂T_x MXene anode and DPE-based electrolyte, highlighting Ti₃C₂T_x MXene's promise as a next-generation anode.