Solid Thin-Film Battery Using a Densely Packed LiNi_0.5Mn_1.5O₄ Crystal Layer

A 5 V-class LiNi_0.5Mn_1.5O₄ (LNMO) positive electrode has excellent potential for increasing the energy density of solid-state Li batteries. In this study, we report the stable cycling of a solid thin-film Li battery using a densely packed LNMO crystal layer, which has a high packing density and a well-developed crystal plane. Annealing a battery reduces the resistance at the interface of a Li₃PO₄ solid electrolyte and LNMO for an order of magnitude, from 5.3 × 10² to 5.7 × 10¹ Ωcm², enhancing the battery performance. This paper lays the groundwork for developing all-solid-state Li batteries using densely packed LNMO layers.