Enabling Extreme Low-Temperature (≤ -100 °C) Battery Cycling with Niobium Tungsten Oxides Electrode and Tailored Electrolytes.

The degradation of current Li-ion batteries (LIBs) hinders their use in electronic devices, electric vehicles, and other applications at low temperatures, particularly in extreme environments like the polar regions and outer space. This study presents a pseudocapacitive-type niobium tungsten oxides (NbWO) electrode material combined with tailored electrolytes, enabling extreme low-temperature battery cycling for the first time. The synthesized NbWO material exhibits analogous structural properties to previous studies. Its homogenous atom distribution can further facilitate Li+ diffusion, while its pseudocapacitive Li+ storage mechanism enables faster Li+ reactions. Notably, the NbWO electrode material exhibits remarkable battery performance even at -60 and -100 °C, showcasing capacities of ≈90 and ≈75 mAh g-1 , respectively. The electrolytes, which have demonstrated favorable Li+ transport attributes at low temperatures in the earlier investigations, now enable extreme low-temperature battery operations, a feat not achievable with either NbWO or the electrolytes independently. Moreover, the outcomes extend to -120 °C and encompass a pouch-type cell configuration at -100 °C, albeit with reduced performance. This study highlights the potential of NbWO for developing batteries for their use in extremely frigid environments.