One Stone, Three Birds: An Air and Interface Stable Argyrodite Solid Electrolyte with Multifunctional Nanoshells.

Li6 PS5 Cl (LPSC) solid electrolytes, based on Argyrodite, have shown potential for developing high energy density and safe all-solid-state lithium metal batteries. However, challenges such as interfacial reactions, uneven Li deposition, and air instability remain unresolved. To address these issues, a simple and effective approach is proposed to design and prepare a solid electrolyte with unique structural features: Li6 PS4 Cl0.75 -OF0.25 (LPSC-OF0.25 ) with protective LiF@Li2 O nanoshells and F and O-rich internal units. The LPSC-OF0.25 electrolyte exhibits high ionic conductivity and the capability of "killing three birds with one stone" by improving the moist air tolerance, as well as the interface compatibility between the anode or cathode and the solid electrolyte. The improved performance is attributed to the peculiar morphology and the self-generating and self-healing interface coupling capability. When coupled with bare LiCoO2 , the LPSC-OF0.25 electrolyte enables stable operation under high cutoff voltage (≈4.65 V vs Li/Li+ ), thick cathodes (25 mg cm-2 ), and large current density (800 cycles at 2 mA cm-2 ). This rationally designed solid electrolyte offers promising prospects for solid-state batteries with high energy and power density for future long-range electric vehicles and aircrafts.

Li(110) lattice plane evolution induced by a 3D MXene skeleton for stable lithium metal anodes.

The non-uniform plating-stripping behaviours of Li metal anodes hinder the application of Li metal batteries. Here, a stable 3D matrix is designed by coating a carbon skeleton with MXene, and the significant influence of the crystallographic texture of Li metal on electrochemical behaviour is investigated. The results demonstrate that the 3D MXene/carbon skeleton can effectively induce the evolution of advantageous Li(110) facets with a dendrite-free anode interface. Consequently, the modified Li metal anodes deliver stable plating-stripping behaviours.

Theoretical formulation of Li3a+bNaXb (X = halogen) as a potential artificial solid electrolyte interphase (ASEI) to protect the Li anode.

A major problem against the realization of high energy density and safe solid Li-ion batteries lies in detrimental reactions at the interface between the lithium anode and the solid electrolytes. This makes it necessary to develop an artificial solid electrolyte interphase (ASEI) as an effective protective coating to the lithium anode, which is the "Holy Grail" to enable high energy density batteries owing to its extremely high capacity. Here in this work, we carried out high-throughput first-principles modelling in the framework of materials genome engineering to identify potential ASEIs based on lithium nitric halides Li3a+bNaXb (X: halogen F, Cl, Br, I). On the basis of comprehensive assessments covering material stability, ionic conductivity, elastic modulus, and electrochemical compatibility with Li and potential SSEs, we have identified lithium nitric halides such as Li6NCl3 as superb ASEI candidates in line with their adequate ionic conductivity and fairly wide electrochemical window from 0 to 2 V (vs. Li/Li+). This makes them compatible with the lithium anode and various well-recognized thiophosphate SSEs such as LGPS, Li6PS5Cl, and Li3PS4, which have typical reduction potentials around 1.71 V. Besides, the large elastic modulus (e.g. 61.12 GPa for Li6NCl3) could be highly effective against the formation of lithium dendrites.