UC San Diego

Improving the extremely low temperature operation of rechargeable batteries is vital to the operation of electronics in extreme environments, where systems capable of high-rate discharge are in short supply. Herein, we demonstrate the holistic design of dual-graphite batteries, which circumvent the sluggish ion-desolvation process found in typical lithium-ion batteries during discharge. These batteries were enabled by a novel electrolyte, which simultaneously provides high electrochemical stability and ionic conductivity at low temperature. The dual-graphite cells, when compared to industry-type graphite ∥ LiCoO2 full-cells demonstrated an 11 times increased capacity retention at -60 °C for a 10 C discharge rate, indicative of the superior kinetics of the "dual-ion" storage mechanism. These trends are further supported by galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) measurements at reduced temperature. This work provides a new design strategy for extreme low-temperature batteries.