Ternary layered double hydroxide cathode materials for electrochemical energy storage: a review and perspective

Abstract

The demand for electrochemical energy storage (EES) with high energy density is increasing with the rapid development of society. Among them, ternary layered double hydroxides (LDHs) have attracted a lot of attention because of their low price and environmental friendliness. More importantly, LDHs with large and adjustable interlayer spacing are ideal candidate materials for cation insertion/doping, which can achieve impressive electrochemical performance. Due to the synergistic effect of different metal ions in ternary LDHs and the synergistic effect of ternary LDHs and other materials in their composites, they provide high specific capacitance/capacity, excellent cycle life, and high energy density. In this review, the crystal structure and preparation of ternary LDHs are reviewed, with an emphasis on their morphology, structural engineering, derivatives and composites, and their applications in EES. In addition, we summarize the challenges facing ternary LDHs as cathode materials for supercapacitors (SCs) and various batteries, such as metal-ion batteries, rechargeable batteries, and metal–air batteries. This review also discusses the charge storage mechanisms of ternary LDHs by various advanced characterization methods.