Researchers at the University of Maryland (UMD) and the US Army Research Lab (ARL) are collaborating on a new type of lithium-ion battery that uses a high concentration of salt in an aqueous electrolyte. They hope to develop a battery that offers greater energy density and better safety than current designs.
â€œLithium-ion batteries raise safety, environmental, and cost concerns, which mostly arise from their nonaqueous electrolytes,â€ write Liumin Suo and colleagues. â€œThe use of aqueous alternatives is limited by their narrow electrochemical stability window (1.23 volts), which sets an intrinsic limit on the practical voltage and energy output. We report a highly concentrated aqueous electrolyte whose window was expanded to ~3.0 volts with the formation of an electrode-electrolyte interphase.â€
The researchers demonstrated a full lithium-ion battery of 2.3 volts that cycled up to 1,000 times, with nearly 100% coulombic efficiency at both low (0.15 coulomb) and high (4.5 coulombs) discharge and charge rates.
The groupâ€™s initial findings, published in Science last November, won backing for a second phase of research, which will begin soon with $4 million in funding for three years. The researchers hope to lower the cost of the electrolytes, enhance energy density and cycle life, and bring out a commercial demonstration cell. Battery firms Liox and Saft will cooperate on commercializing aqueous batteries for use in EVs.
Source: University of Maryland