Solid-state batteries (SSBs) promise enhanced safety and energy density, but their performance under practical low stack pressures (<1 MPa) remains limited by interfacial failures due to electrode chemomechanical properties. While anode chemomechanics have been extensively studied, this work reveals the critical role of cathode chemomechanics in governing Li metal plating/stripping behavior and SSB stability. Using LiCoO2 cathodes with controlled crystallographic texture, we demonstrate that cathode lattice strain anisotropy during cycling significantly influences Li plating and stripping behavior and void formation at stack pressure below 5 MPa. Electrochemical impedance spectroscopy and critical current density tests confirm that cathodes generating negative stress during delithiation suppress void formation and enable long-term cycling at high areal capacities (5 mAh/cm²) and current densities (>1 mA/cm²) under 1 MPa pressure and room temperature, without interlayers or elevated temperatures. These findings establish cathode chemomechanics as a key design parameter for SSBs, offering a pathway toward practical SSBs.
