The energy densities required to electrify aviation, heavy machinery, and robots (~1,000 Wh kg^-1) seem insurmountable with current battery architectures based on solid intercalation materials (~250 Wh kg^-1), but animals can store ~2,000 Wh kg^-1 and operate continuously. The clear gaps in specific energy and operational capability between machines and animals motivate new ways to extract electrochemical energy via bioinspired designs. This talk will report our advances in an electrochemical stomach and novel catholyte compositions that near-continuously powers electric aircraft and robots by ingesting small molecules as beverages and converting that chemical energy to electricity by pairing them with metals. The discharge reaction is engineered so that the beverage maintains a liquid phase to boost the active material ratio in the stomach and fully convert the molecules at high current outputs. The slow electrical recharge of conventional batteries is replaced by rapid reingestion of catholyte beverages. Using dimethyl trisulfide (CH₃S₃CH₃) and lithium (Li) metal, we demonstrate a 10.4 Ah stomach that delivers a specific energy of up to 850 Wh kg_stomach^-1 at 192 A kg_stomach^-1 and restores the chemical energy in 1 minute. The stomach powered a commercial quadcopter and doubled the flight time of the manufacturer’s state-of-the-art batteries. The used beverages were recycled back to CH₃S₃CH₃and Li metal in an external electrochemical cell, which were reused in the stomach. As a sustainable energy cycle, the stomach is more cost-efficient than batteries and even gasoline, and the catholyte can be stored for three years and discharged at -20 ^oC while retaining it's kinetics and energy density. Owing to the diversity of small molecules, we tailor the composition of beverages to enable 1,447 Wh kg^-1 discharge specific energy or fire-safe energy storage. We will discuss the microscale electrode architecure, electrolyte chemical composition, and SEI that enable the stomach performance.

Jason Jolly

Appearances