(Invited) Atomically-Precise Interfacial Materials and Design of Solid-State Batteries
Authors: Sun Andy Xueliang 
Published: February 2020

The state-of the-art rechargeable Lithium-ion batteries (LIBs) use liquid electrolytes and are the major choice for current EVs and portable electronic applications. However, these LIBs still suffer from many issues related to safety, lifespan and energy density. Accordingly, solid-state lithium batteries (SSLBs) have recently emerged as a promising alternative energy storage device due to their ability to overcome the intrinsic disadvantages of liquid-electrolyte LIBs and possess a greater volumetric energy density due to the use of solid-state electrolytes (SSEs). However, the interfacial issues between SSEs and electrodes (both cathode and anode) have a significant impact on the stability and lifetime of SSLBs [1-2]. The origin of these interfacial phenomena is the unstable contact and chemical reactions between electrodes and electrolytes to form an interlayer with extremely low electronic and/or ionic conductivities, which restricts the performance of the SSLBs. An artificial, uniform and ultrathin interfacial layer is critical to address these challenges [2]. 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 [2].
Our work applys ALD/MLD to rationally design novel coatings to address the interfacial challenges in SSLBs. The goal is to prevent capacity degradation of SSLBs caused by high interfacial resistance and chemical/electrochemical reactions between electrodes and electrolytes. We will demonstrate 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.
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