Advanced Neutrally Buoyant Rechargeable Batteries Based on Ceramic Electrolyte Separators

A pressure tolerant, neutrally buoyant, high-energy density battery is proposed that utilizes a Li+ conducting, solid-electrolyte separator, LiSICON. The LiSICON ceramic is fabricated using state of the art tape casting methods which allows composite structures of porous and dense layers ~100mm thick. The layered structure increase mechanical strength and decrease interfacial and bulk resistances. The high-energy cathode material, amorphous MnO2 or nano-crystalline LiMn1/3Ni1/3Co1/3O2, allow a predicted energy density >400 Whr/kg for the overall battery. The use of a lightweight lithium metal anode results in a battery with an estimated specific gravity approaching 1. The pressure tolerant battery design allows the case to preferentially deform to compensate for increasing pressure and also accounts for the internal volume change during battery discharge. The solid electrolyte separator prevents lithium dendrites from shorting the battery during recharge significantly increasing the safety margin, inherent in alkali metal batteries.