Advanced lithium-ion (Li-ion) batteries are currently under development for Extravehicular Activity Suits, Altair Lunar Landers, and Lunar Mobility Systems. However, low voltage operation and low capacity cathode of current Li-ion batteries limits both volumetric and gravimetric energy density. High capacity cathode materials with high voltage operation are needed to offer the required gains at the integrated cell level to meet NASA's goal. Lynntech proposes to develop advanced cathode that can work at high potential and provide high capacity, long cycle life, and high rate capability. During Phase I project, Lynntech will synthesize the cathode materials, optimize the compositions and structures, evaluate the cathode's properties, and determine the performance of cathodes in half cell and full cell containing high voltage electrolyte and silicon-carbon composite anode. The technology is currently estimated at TRL 3 and is expected to result in TRL 4 at the end of the Phase II project. The advanced cathode can enable ultra energy density Li-ion batteries which can provide significant mass and volume savings and operational flexibility for NASA near-term exploration missions.