Enhancement of Li+ ion Tranport in High Energy Solid State Li-ion Batteries.

摘要

Li-ion battery (LIB) is one of the major candidates for the future form of the energy storage system. However, the ignitability of organic liquid electrolyte is the primary obstacle for the large scale-up of LIB systems. Solid state Li-ion batteries (SSLIBs) with nonflammable solid state electrolytes (SSEs) are expected to be one of the solutions. Nevertheless, SSLIBs suffer from fast degradation and low power density because of limitations at interfaces in SSLIBs. This dissertation demonstrates efforts to address interfacial limitations in SSLIBs. Al2O3 atomic layer deposition (ALD) on a high voltage cathode material successfully reduces the resistive layer growth at active material/SSE interfaces during battery cycling. In addition, thermal treatment of Al2O3 ALD layer around active material particles utilizes Al2O3 ALD layer as Li+ ion pathway providing additional access to Li+ ion intercalation sites on active material which will induce an increase in energy. Employing gradients of SSE portion in working electrodes and the combination of enhanced electrodes are described in the latter part of this dissertation as continuing studies toward the commericialization of SSLIBs with stable cycling and high energy/power density. This dissertation provides effective strategies to overcome interfacial issues in SSLIBs, aiming for the goal to outperform current LIBs.