Phase‐Changeable Dynamic Conformal Electrode/electrolyte Interlayer enabling Pressure‐Independent Solid‐State Lithium Metal Batteries

Lithium-metal-based solid-state batteries (Li-SSBs) are one of the most promising energy storage devices due to their high energy densities. However, under insufficient pressure constraints (-3 S cm-1 , attributed to the shortened steric solvation hindrance and optimized Li+ coordination structure. Furthermore, the changeable phase property of the interlayer endows Li-SSBs with a healable Li/SSE interface, accommodating the stress-strain evolution of the lithium metal and constructing the dynamic conformal interface. Consequently, the contact impedance of the modified solid symmetric cell exhibits a pressure-independent manner and does not increase over 700 h (0.2 MPa). The LiFePO4 pouch cell with the phase-changeable interlayer shows 85% capacity retention after 400 cycles at a low pressure of 0.1 MPa.