Abstract
The key challenge in all-solid-state batteries (ASSBs) is establishing perfect physical contact between rigid components for facile interfacial charge transfer, especially between the solid electrolyte and cathode. Here, we introduce a new class of shapeable inorganic-based solid electrolytes with a liquid-like sublattice that can form intimate contact with the rigid cathode. The electrolyte exhibits extraordinary clay-like mechanical properties (storage and loss moduli < 1 MPa) at room temperature, high lithium ion conductivity (3.4 mS cm-1), and a glass transition below -50 ℃. The unique mechanical features provide liquid-like penetration into the porous cathode and ionic conduction paths for all cathode particles, delivering a high energy density. We propose a design principle that the complex anion formation including Ga, F and a different halogen can induce the clay-like features. Our findings provide new opportunities in the search for solid electrolytes and suggest a new approach for resolving the issues caused by the solid electrolyte–cathode interface in ASSBs.