Low-Temperature High-Rate Capabilities of Lithium Batteries via Polarization-Assisted Ion Pathways

On-board vehicle applications dictate the need for improved low-temperature power densities of rechargeable batteries. Integration of high-permittivity artificial dielectric solid electrolyte interfaces (SEIs) into the lithium ion battery architecture is a promising path to satisfy this need. The relationship between the permittivity of various artificial dielectric SEIs and the resulting high-rate capability at low temperatures is investigated. Room-temperature studies reveal a weak relationship between these variables. However, at low temperatures, the correlation between the larger permittivity of the dielectric SEIs and the greater high-rate capabilities of the cells is striking. The high-rate capabilities for pulsed laser deposition-synthesized cathode thin films with various BaTiO3 (BTO) SEIs covering configurations are evaluated. A remarkable improvement in the high-rate capability is observed for LiCoO2 (LCO) modified with dot BTOs, while the rate capability for planar BTO (fully covered LCO) is weakened significantly. A series of experimental results prove that a large polarization, P, in the dielectric SEIs intensified with permittivity accelerates interfacial charge transfer near the dielectrics-LCO-electrolyte triple junction.