INVESTIGATIONS ON AN AQUEOUS LITHIUM SECONDARY CELL

The deposition and stripping of lithium from different substrates has been investigated in saturated aqueous solutions of LiCl/LiOH to asses s the possibility of developing a secondary lithium battery with high energy density and high power density, and based on water as a solvent . On mercury electrodes, a low catalytic activity for hydrogen evoluti on is observed, together with a positive shift in potential on amalgam ation. This means that lithium deposition is the predominant electrode reaction at negative potentials. Indeed, the lithium charge recovery at a mercury anode is 98.5%. Other practical anode materials, however, fail to give a charge recovery anywhere close to this value. Anode ma terials investigated include metals that alloy with lithium and materi als that form lithium insertion compounds. Manganese dioxide appears t o be an effective cathode material for a battery using saturated LiCl/ LiOH as the electrolyte. The positive electrode reaction at MnO2 in th is medium is shown to be lithium insertion rather than protonation, an d acceptable rechargeability is observed.