Direct contact shield of LiMn₂O₄ active material from electrolyte

The spinel LiMn₂O₄ powders were prepared by solgel technique using lithium acetate (Li(CH₃COO) · 2H₂O) and manganese acetate (Mn(CH₃COO)₂ · 4H ₂O) as starting materials, citric acid as a chelating agent, and acrylamide as a gel formatting agent. In order to improve the electrochemical performance of lithium ion batteries and prevent structural disintegration from Mn dissolution generated by undesirable acid production, conductive agents were additionally coated on the surface of active material coated on pure aluminum foil as a current collector. Also, it was comparatively investigated using different conductive agents with different particle sizes as well as adopting the cells into the different thermal environments. The electrochemical performance of the Li/LiMn₂O₄ cells demonstrated that the spinel LiMn₂O₄ might be effectively shielded from acid, resulting in improved electrochemical capacity characteristics at room temperature as well as elevated temperature of 55°C.