Controllable Solid Electrolyte Interphase in Nickel-Rich Cathodes by an Electrochemical Rearrangement for Stable Lithium-Ion Batteries

Abstract

The layered nickel-rich materials have attracted extensive attention as a promising cathode candidate for high-energy density lithium-ion batteries (LIBs). However, they have been suffering from inherent structural and electrochemical degradation including severe capacity loss at high electrode loading density (>3.0 g cm⁻³) and high temperature cycling (>60 °C). In this study, an effective and viable way of creating an artificial solid–electrolyte interphase (SEI) layer on the cathode surface by a simple, one-step approach is reported. It is found that the initial artificial SEI compounds on the cathode surface can electrochemically grow along grain boundaries by reacting with the by-products during battery cycling. The developed nickel-rich cathode demonstrates exceptional capacity retention and structural integrity under industrial electrode fabricating conditions with the electrode loading level of ≈12 mg cm⁻² and density of ≈3.3 g cm⁻³. This finding could be a breakthrough for the LIB technology, providing a rational approach for the development of advanced cathode materials.

A nickel-rich cathode material with homogeneous artificial solid–electrolyte interphase (SEI) layer is developed via a simple, one-step process involving an SEI precursor. The initial artificial SEI compounds are electrochemically rearranged by reacting with the by-products such as acidic species, which enhances the structural and thermal stability. The cathode material demonstrates a high specific capacity and stable interfacial properties.

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