Operando study of the unique behavior of CuS in all-solid-state batteries (SSBs)

CuS is a conversion material with around 75% volume change during cycling. Unlike other conversion materials, which form nano-sized metal clusters distributed in LiaXb matrices after lithiation, we found that a micron-sized Cu network appeared in CuS SSBs after discharge. We believe this network originates from a macroscopic displacement reaction, but the details are still unclear. To overcome the solid nature of SSBs, nondestructive tomography has been employed in our previous in-situ study but the diffusion of Cu over micrometer scale, across many primary CuS particles in SSBs is still unidentified. To answer these unidentified scientific questions, operando synchrotron 3D tomography at BM05 at ESRF is planned to unravel the structural variation and follow the Cu diffusion within SSBs.