Electro-chemo-mechanical evolution of sulfide solid electrolyte/Li metal interfaces: operando analysis and ALD interlayer effects

Abstract

Investigation of interfacial degradation of Li10GeP2S12 (LGPS) electrolytes and the effect of ALD artificial SEI interlayers in lithium metal solid state batteries using a suite of operando microscopy and spectroscopy techniques.

Surface Engineered Li Metal Anode for All‐Solid‐State Lithium Metal Batteries with High Capacity

“…It has been verified theoretically and experimentally that Li reacts with LGPS spontaneously once they contacted forming byproducts with low ionic conductivity and electric conductive LiGe alloy [6] . The continuous decomposition of LGPS destroys the integrity of interface seriously due to the large volume changes, which finally causes short circuit [7] . Thus, it is of great importance to improve the interfacial stability between LGPS and Li metal.…”

“…The reaction redundant by‐products such as Li 2 S, Li 3 P, and LiGe alloy would accumulate at the interface causing the increase of interface resistance and impede Li + ions transfer [6] . Moreover, the accompanied inevitable volume changes would create new defects (cavities, holes, and fractures) at the interface [7] . Once Li + ion is deposited, it preferably nucleates at spots with high ionic and electronic conductivity, then grows toward to the unlimited space, resulting in the formation lithium dendrite.…”

“…[6] The continuous decomposition of LGPS destroys the integrity of interface seriously due to the large volume changes, which finally causes short circuit. [7] Thus, it is of great importance to improve the interfacial stability between LGPS and Li metal. Up to now, various approaches have been applied to overcome this problem, including tuning the crystal structure of LGPS by doping, [8] replacing Li metal with lithium alloys, [9] introducing artificial solid electrolyte interface by modifying Li metal surface with salts or acids and so on.…”

“…Up to now, various approaches have been applied to overcome this problem, including tuning the crystal structure of LGPS by doping, [8] replacing Li metal with lithium alloys, [9] introducing artificial solid electrolyte interface by modifying Li metal surface with salts or acids and so on. [7,10] It is reported that the cycle life of all-solid-state LiCoO 2 /sulfide/Li was greatly improved by introducing a 20 nm silicon layer at the electrolyte/Li interface by pulsed laser deposition. [11] Unfortunately, due to the limited energy density, cost and process difficulties, none of them meet the requirements for the commercialization of ASSLMBs.…”

“…[6] Moreover, the accompanied inevitable volume changes would create new defects (cavities, holes, and fractures) at the interface. [7] Once Li + ion is deposited, it preferably nucleates at spots with high ionic and electronic conductivity, then grows toward to the unlimited space, resulting in the formation lithium dendrite. As for the Li@Li 3 PO 4 electrode, the dense Li 3 PO 4 layer firstly prevents the contact between Li and LGPS, which cuts off the source of side reactions resulting in an enhancement of the interface stability and integrity.…”