Exploiting mechanistic solvation kinetics for dual‐graphite batteries with high power output at extremely low temperature

Abstract 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 ∥ LiCoO${}_2$ 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. (© 2019 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)