In situ interphase engineering for all-solid-state Li batteries: a case study on the LiNi0.5Mn1.5O4/Li0.33La0.55TiO3 composite cathode guided by ab initio calculations

Abstract

The sinterability and interfacial stability issues in the composite cathode have been the main bottlenecks of oxide-based all-solid-state Li battery development. The interfacial reaction between the electrode and electrolyte plays an important role in the sinterability and interfacial stability of a composite cathode. A suitable interfacial reaction can not only improve the sinterability by providing an additional driving force for chemical bond formation, but it can also stabilize the electrode/electrolyte interface by forming interfacial reaction products which remain stable during operation of the cell. In this work, a suitable dopant that can induce the formation of the desired interphase between the LiNi_0.5Mn_1.5O₄ cathode and Li_0.33La_0.55TiO₃ electrolyte was obtained through ab inito computational screening. Experimental verification was carried out by field-assisted sintering technology/spark plasma sintering (FAST/SPS) for obtaining mechanically stable composite cathode pellets and heat treatment for inducing the interfacial reaction. The dopant identified by computation was proven to induce the in situ formation of a stable protective layer. A successful method of simultaneously improving sinterability and interfacial stability in an oxide-based composite cathode is demonstrated in this work.