In this Air Force STTR project, Bioenno Tech in teaming with Washington State University (WSU) proposes to develop a novel class of a novel class of highly safe, low temperature capable, high energy density all-solid-state Li-ion batteries (ASSLiBs) for aircraft applications. It is based on a unique combination of our proprietary solid-state polymer composite electrolyte and a novel design of 3D-networking composite electrodes. This electrolyte will provide high ionic conductivity and wide operating temperature ranges along with good compatibility with designed 3D-networking composite electrodes. By integrating this class of electrolytes with properly designed high energy electrodes, interface resistance can be minimized. The resultant ASSLiBs are expected to offer more desirable performance such as enhanced energy/power densities, improved cyclability, and excellent safety as compared with commercially available Li-ion battery based on liquid electrolyte. In addition, the proposed ASSLiBs can be processed using mature multi-layer hot-pressing technology, allowing for the cost-effective scalable mass production. Phase I will focus on the feasibility demonstration of the proposed technology, through material design, processing, prototyping and characterizations. Sub-scale ASSLiBs pouch cells will be prototyped and demonstrated. In Phase II, further optimization and scaling up will be carried out in order to produce ASSLiBs full-scale pouch cells (e.g. 3.6V5Ah) and the associated battery systems (e.g. 6T 28V60Ah), which would pave the way to enable the successful development of a commercially viable ASSLiBs product for aircraft and other military/civil applications.