Solid-state batteries are developed to integrate the lithium metal anode and provide a step-change in battery performance. Recent progress made with the manufacture and processing of inorganic solid electrolytes has demonstrated the feasibility of this approach [1]. Still, there remain challenges to be overcome at the anode and cathode interfaces regarding contact and electrochemical stability. There are two key technological requirements to make a powerful solid-state battery: creating a composite cathode with high energy density and rate capability while minimizing the amount of all other cell components (solid electrolyte separator and anode). Both challenges and design requirements at anode and cathode are discussed.<br/>Often, contact loss and electrochemical degradation in the cathode limit cell performance and result in capacity fade. Therefore, the electronic and ionic charge transport bottlenecks in composite cathodes are quantified using purpose-built cells. The ionic and electronic partial conductivities are explored to deduce the limiting factors for the cycling rate. Dependent on the content of cathode active material, the respective effective conductivities are correlated with the microstructure of the composite cathodes and the cell performance [2]. In addition, electrochemical degradation of the solid electrolyte increases the internal cell resistance, which decreases the cell performance.<br/>The lithium metal anode is equally challenging to realize. Even when the solid electrolyte is electrochemically stable with lithium metal, pressure-free cycling is hampered by contact loss during stripping of lithium. This can be mitigated by the addition of an ionic liquid interlayer. Thus, it is demonstrated that the pressure-free stripping of lithium can be prolonged to higher capacity before an increase in cell potential stops the continuation of the stripping process [3]. Combining both anode and cathode design strategies is important in developing and improving lithium solid-state batteries.

Design strategies for anode and cathode of lithium solid-state batteries

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.