(Invited) All Solid-State Batteries: From Interface to New-Type Electrolytes

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All-state-state lithium batteries (ASSLBs) have gained worldwide attention because of the high ionic conductivity of SEs, intrinsic safety and improved energy density. In ASSLBs, solid-state electrolyte is a key component. Compared with polymer-based and oxide-based electrolytes, sulfide-based electrolyte generally exhibits the highest ionic conductivity (10-3 ~ 10-2 S/cm) and favorable mechanical property. However, the serious interfacial challenge, bad air stability, narrow electrochemical windows of sulfide-based electrolyte significantly impede development of sulfide-based ASSLBs. Generally, an artificial, uniform and ultrathin interfacial layer is critical to address these challenges. Atomic layer deposition (ALD) and molecular layer deposition (MLD) are unique coating techniques that can realize excellent coverage and conformal deposition with precisely controllable at the nanoscale level due to its self-limiting nature, which are ideal for addressing the challenges of interface in SSLBs.In this talk, I will demonstrate to apply ALD/MLD to (i) stabilize the interface between cathode electrodes and electrolytes and prevent the formation of intrinsically high resistance layers, (ii) suppress elemental inter-diffusion during the operation of SSLBs, (iii) fabricate facile ionic transportation channels to facilitate ion exchange between different components of SSLBs, and (iv) buffer volume changes during cycling of SSLBs [1] .In this talk, I will talk about halide-based electrolyte for ASSLBs. Compared with sulfide-based electrolyte, both experimental and theoretical results recently demonstrate that halide-based electrolytes have more advantages including high RT ionic conductivity (>10-3 S cm-1, theoretically possible 10-2 S cm-1), wide electrochemically stable window (possible up to 6 V), high air-stability, good stability toward oxide cathode materials, and even salable water synthesis strategy [2-3].