High-pressure field assisted sintering of half-cell for all-solid-state battery

Abstract

High-pressure field assisted sintering (FAST/SPS) of half-cell for all-solid-state Li batteries was proposed and tested. The half-cell included the layer of lithium lanthanum zirconate (LLZO) electrolyte and the layer of mixed cathode. The mixed cathode consisted of lithium cobalt oxide (LCO) used as energy storage material and LLZO used as ionic conductor. A tool made of TZM molybdenum alloy was used to apply a high pressure of 440 MPa during FAST/SPS at a temperature of 675 °C ensuring stability of materials. An average relative density of sintered half-cell was around of 95%. The half-cell was assembled with a lithium anode and electrochemically tested. The results were compared with the performance of a half-cell sintered in an established graphite tool at the same temperature but under a lower pressure of 50 MPa and with a lower density (around of 78%). The battery with half-cell sintered at high pressure showed two-fold larger surface storage capacity. Further optimization of materials and processing is in progress.