An electrochemical system for continuously powering robots through the ingestion of energy-dense organic molecules, utilizing a new electrolyte that enables the maximization of material performance. This system also provides a method for recycling and reusing the materials used in the stomach.

The electrification of existing battery-powered systems is hampered by the significant time required for charging and recovery. Due to this inherent limitation, robots and electric vehicles have restricted operational time; overcoming these constraints requires a substantial increase in energy and power density. Conversion reaction battery systems that use lithium-sulfur (Li-S) and Li-air can meet the energy demand aspect, but are difficult to recharge or recover, making them uneconomical. For example, the mass-produced rechargeable batteries have energy densities below 250 Wh kg-1, while short-range all-electric aircraft typically require 750 to 2,000 Wh kg-1. These factors contribute to the increased cost of these vehicles, and consequently, handling the energy needs remains a significant challenge throughout their lifetime.

An energy system composed of a converter, a catholyte, and an anode, where the catholyte and anode can be replenished, recovered, and “recharged” for re-use. The method could serve as an alternate strategy that would (a) increase energy density and (2) permit exchange of energy storage to prolong the use time.

The inventors developed an electrochemical system that can help rapidly regain energy and power density by ingesting liquids or solids. The solution pairs redox-active organic small molecules stored in a liquid catholyte, such as dimethyl trisulfide (CH3S3CH3), with metal anodes in a refillable electrochemical cell (also referred to as a stomach). This catholyte system could provide continuous energy and meet higher energy and power density demands. To achieve a high current output of 193.5 A kgstomach-1, a current collector is designed, and the catholyte composition is altered to prompt the CH3S3CH3 transport and prevent electrode polarization. Experiments demonstrate that a 43.7 Ah electrochemical cell (stomach) with CH3S3CH3 and Li could achieve an energy density of 918.7 Wh kgstomach-1 and provide power for 23.4 hours in a 24-hour period with 5 refills of catholyte. Unlike fuels in engines and fuel cells, the catholyte and Li are recyclable with electrical input and can be reused in this system.

• This technology can be employed in systems that require a higher energy density.
• This invention could help quickly replenish energy availability in rechargeable systems.
• The catholyte and Lithium utilized in this system can be recycled with electrical input and reused in the system.
• The Li-specific recycling efficiency of 99.98% (lab demonstrated) is a solid advantage.
• For robot and aircraft applications, the system could be cost-efficient than the existing rechargeable batteries and gasoline-based power systems.