A new class of rechargeable Li-ion batteries with an energy density greater than 450 Wh/kg (and volumetric density of at least 1000 Wh/L) with good zero degree performance is needed for use in the EVA spacesuit in future human missions. In addition to the energy density consideration, the battery needs to be safe for human operation, and have a calendar life in excess of 5 years. The cells should be sufficiently robust to withstand abuse, and not be susceptible to thermal runaway. The proposed program aims to demonstrate that a cathode material based on conversion mechanism can be engineered and assembled into a practical battery that meets NASA's requirements. In addition to addressing the EVA spacesuit battery requirements, the proposed technology has wider ramifications for other NASA needs (e.g., Human Lunar and Mars Landers and Rovers) where the energy density requirements are lower, but cycle life expectations are greater.
Li-ion batteries are ubiquitous, having found use in portable devices, electric vehicles, stationary power storage, and myriad other applications. According to one estimate, Li-ion batteries account for more than 35% of the market for batteries, which is projected to be $120 billion by 2019. Virtually all Li-ion batteries use intercalated metal oxide materials as the cathode. This fundamentally limits the energy density of the material. The proposed program aims to advance the state of the art of conversion-based cathode materials so as to lead to a near doubling of the energy density from current levels.