Solid State Batteries (SSBs) represent an innovative approach to energy storage, distinct from the established Lithium-ion batteries (LIBs). Conventional LIBs face challenges meeting future energy density, safety, and cost standards due to the limitations of their liquid electrolyte systems.
SSBs, specifically All Solid State Batteries (ASSBs), offer a promising alternative to LIBs. The fundamental difference lies in the electrolyte used that addresses several challenges associated with liquid electrolytes, including safety risks like fire and explosion due to their poor thermal stability and low flash points. The formation of a solid electrolyte interface (SEI) in LIBs leads to efficiency degradation and dead lithium accumulation, while liquid electrolytes also contribute to lithium dendrite formation, creating short-circuits and capacity loss.
In contrast, Solid Electrolytes enhance operational safety as they are inflammable and heat-resistant, preventing leakages or gas production within the cells. They also have the potential to increase energy density and are less likely to cause adverse effects, contributing to an extended life expectancy.
Few Challenges with All Solid State Batteries:
The mass transfer in these batteries occurs exclusively through the vacancy-diffusion process within the solid space charge layer, where kinetics are slower compared to the semi-infinite diffusion in liquid electrolytes. Optimizing the crystallographic arrangement of these battery components is crucial for efficient lithium ion movement, and recent focus has been placed on interfacial design and crystal engineering to improve their performance.
Additionally, 'issues at the interface between components are significant obstacles'. The ion mobility at the interface between the electrode and the electrolyte in these batteries can decrease due to improper interphase formation and a resistive space charge layer, leading to internal resistance, lithium dendrite formation, and strain energy from electrolyte deformation. This results in high resistance, reduced coulombic efficiency, low power performance, and shortened battery life as mentioned in one of the papers by Choi et. al. (2023) [1].
All Solid State Batteries, with their solid electrolytes, offer a promising solution to most of the limitations of conventional LIBs, providing enhanced safety, increased energy density, and longer life expectancy. However, challenges, particularly at the interface between the electrode and electrolyte, need addressing to fully realize their potential.