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.

Metal organic decomposition (MOD) using octylic acid salts was applied to synthesize a BaTiO3–LiCoO2 (BT–LC) composite powder. The Ba and Ti octylates were utilized as metal precursors, in an attempt to synthesize homogeneous BT nanoparticles on the LC matrix. The BT–LC composite, having a phase-separated composite structure without any impurity phase, was successfully obtained by optimizing the MOD procedure. The composite prepared using octylate precursors exhibited a sharper distribution and better dispersibility of decorated BT particles. Additionally, the average particle size of the decorated BTs using metal octylate was reduced to 23.3 nm, compared to 44.4 nm from conventional processes using Ba acetate as well as Ti alkoxide as precursors. The composite cathode displayed better cell performance than its conventional counterpart; the discharge capacity of the metal octylate-derived specimen was 55.6 mAh/g at a 50C rate, corresponding to 173% of the capacity of the conventional specimen (32.2 mAh/g). The notable improvement in high rate capability obtained in this study, compared with the conventional route, was attributed to the higher density of the triple junction formed by the BT–LC–electrolyte interface.