Design Wide-Temperature and Fast Charging Battery Electrolyte

Improving the wide temperature operation of rechargeable batteries is vital to the operation of electronics in extreme environments, where systems capable of higher energy, high-rate discharge and long cycling are in short supply. In this talk, we will show electrolyte designs to achieve high-energy density and stable cycling performance in wide temperature range. We will first demonstrate the holistic design of dual-ion batteries, which circumvent the sluggish ion desolvation process found in typical lithium-ion batteries during discharge. These batteries are enabled by a novel ester electrolyte, which simultaneously provided high electrochemical stability and ionic conductivity at low temperature. The dual-ion cells, when compared to industry-type graphite <i>||</i> LiCoO₂ full-cells demonstrated an 11 times increased capacity retention at -60 ^oC for a 10 C discharge rate, indicative of the superior kinetics of the “dual-ion” storage mechanism. More importantly, the fundamental understanding developed for dual-ion cells was then extended to search for other high-capacity, high-rate electrodes, which leads to further improved energy density and stability for both high and extremely low temperatures, demonstrated by rechargeable Li metal batteries using both high-Ni oxide and sulfur cathodes.