Lithium-Ion Battery Cathode-Electrolyte Interface

Abstract

The global energy crisis, consumption of fossil fuels, and the associated environmental issues have stimulated extensive interest in searching for sustainable energy storage and conversion systems. Rechargeable lithium-ion batteries (LIBs) are widely used in mobile devices, hybrid, and electric vehicles. Electrode-electrolyte interface has a strong impact on battery capacity decrease and long-term cycling stability. In order to improve fundamental understanding of the involved phenomena to accelerate the rational design of cathode materials and stable interface, Li(Ni,Co,Mn)O2 (NCM) is a cathode material for rechargeable LIB and also a promising electrocatalyst for oxygen evolution reaction (OER). Their battery performance and catalytic activity are highly correlated to their structures. Multiple processes occurring at the cathode/electrolyte interface led to overall performance degradation. One failure mechanism is the dissolution of transition metals from the cathode. Our efforts employ thin film as a model cathode to monitor the Mn dissolution. Using LiMn2O4 and NCM as cathode materials, we will focus on electrochemical characterization, cation mixing, oxygen evolution, and thin film deposition with controlled crystal structures and composition. We will further introduce our work employing the scanning electrochemical microscope to study LIBs degradation and cathode-electrolyte interface in situ and in real-time.