Correlating lithium-ion transport and interfacial lithium microstructure evolution in solid-state batteries during the first cycle

The formation of heterogeneous Li structures at the anode/solid polymer electrolyte (SPE) membrane interphase of solid-state Li-metal batteries (SSLMBs) is one of the key factors that impede SSLMB performance. The relationship between Li+-ion transport kinetics and Li0 structural evolution at the buried interphase is critical but challenging to characterize. Here, we report an operando correlative X-ray Compton scattering and computed tomography imaging technique that quantifies the changes of Li+-ion concentrations in the bulk cathode, SPE membrane, and anode of the SSLMB full cell using a commercially standard configuration. We then visualize Li+-ion concentration distributions as well as Li0 microstructures at the buried anode/SPE interphase. Mechanistic analyses show that the Li-stripping step forms more irregular interfacial Li morphologies at the expense of bulk anode volume shrinkage compared to the Li-plating step during the first cycle. [Display omitted] •Operando correlative X-ray Compton scattering-computed tomography (XCS-CT)•XCS-CT is used to distinguish Li+ and Li0 changes in solid-state Li-metal batteries•XCS maps Li+-ion concentrations of cathode, anode, solid polymer electrolyte•CT reveals Li0 morphology at buried anode/SSE interphase inside full cell Huang et al. report an operando correlative X-ray Compton scattering and computed tomography imaging technique that correlates Li+ concentration changes with Li morphology changes at the buried metal anode/solid polymer electrolyte interphase inside solid-state batteries. The study indicates that the stripping step forms irregular interfacial lithium morphologies at the expense of bulk anode volume shrinkage during the first cycle.