Science Vertical I

Solid-state batteries (SSBs) are promising next-generation energy storage devices that can significantly improve the energy density and power density of conventional lithium-ion batteries. Despite their theoretical promise, the advancement of SSBs requires a fundamental understanding of mechanistic aspects including electrochemical-mechanical interaction, morphological growth, and transport-kinetics dichotomy at various solid-solid interfaces. A comprehensive mapping of the mechanistic interaction within the solid-state battery system and their influence on the underlying modes of failure and degradation will be interrogated in this science vertical.

Most importantly, with the incorporation of an energetic anode material such as lithium metal, and with the requirements of high energy density and fast charging in SSBs, a bottom-up understanding and analysis of safety will be achieved. For such solid-solid interfaces, microstructures, and morphologies, we hypothesize that the underpinning thermo-electrochemical-mechanical interactions at scales are deeply coupled with the safety-degradation-performance response.

With respect to the lithium metal-solid electrolyte interface, a wide range of candidate mechanisms including species molar volume, interface energetics, grain boundary arrangement and pore connectivity in the solid electrolyte microstructure, and mechanical properties of the lithium metal and solid electrolyte affect the electrodeposition stability. On the other hand, the competing interaction between electrochemical reaction, transport, lithium self-diffusion and mechanics governs the onset of void nucleation and growth during stripping of the metal anode.

Driven by the intrinsic asymmetry, and heterogeneity in the underpinning mechanisms, the plating-stripping behavior in SSBs involves distinct failure mechanisms and implications on safety. Along similar lines, the electrochemical-mechanical-transport-chemical processes that occur at interfaces dictate the degradation, electrochemical performance, and safety characteristics of the solid-state cathode. In contrast to liquid electrolyte systems, the presence of solid-solid point contacts is a critical attribute in solid-state cathodes that induces additional kinetic-transport limitations and heterogeneities.

The crystallographic, morphological, and structural interaction between the solid electrolyte and active material, and their mechanical and electrochemical characteristics govern the interface contact, stress distribution, and reaction heterogeneity. Overall, the electro-chemo-mechanical response of the cathode including particle-particle interaction and thermal stability characteristics of the electrode material (e.g., oxygen liberation) will be comprehensively analyzed to understand the safety response of solid-state batteries.