An integrated study on the ionic migration across the nano lithium lanthanum titanate (LLTO) and lithium iron phosphate-carbon (LFP-C) interface in all-solid-state Li-ion batteries

A major challenge for the development of all-solid-state lithium-ion batteries (ASS-LIBs) relay on the development of an ideal electrolyte material and solving the interfacial issues at the electrode-electrolyte interface. Nano-crystalline lithium lanthanum titanate (LLTO) and lithium iron phosphate-carbon (LFP/C) has been prepared as electrolyte and cathode material for a solid-state lithium ion cell (LIBs). Prepared lithium lanthanum titanate, lithium iron phosphate-carbon and the composite powders were subjected to structural, optical, morphological and electrochemical characterizations. The high ionic conductivity of lithium lanthanum titanate (1.06 × 10−4), carbon coated lithium iron phosphate (5.01 × 10−5) and their interface (6.00 × 10−5) designate the pertinence of their full cell configurations. The full cell assembly has been characterized electrochemically to evaluate the performance of the interface. The assembled ASSBs show cyclability up to 55 initial cycles, with the nano-LLTO/LFP-C interface. The line scan analysis has been performed to identify the cation movement and accumulation of ions towards and across the cathode-electrolyte interface after cycling. The present study provides new direction and methodology for the detailed interface analysis across the nano-electrode- nano-solid electrolyte layer in all solid-state assemblies.