Energy storage mechanisms of metal selenides and application in lithium-ion capacitors

Lithium-ion capacitors （LICs） are novel power energy storage devices， which have the advantages of both lithium-ion batteries and electric double-layer capacitors. However， the slow electrochemical dynamics of the battery-type anode limits the application of LICs. Metal selenides have attracted much attention because of their excellent conductivity， rapid reaction kinetics and high theoretical capacity. In this paper， the classification， structure and properties of metal selenides are systematically introduced， and three energy storage mechanisms of intercalation mechanism， conversion mechanism and alloying mechanism are discussed.Finally， the impacts of structural regulation， carbon material synergy， and bimetallic selenide construction on the electrochemical performance are analyzed. The application of metal selenide materials with structurally stable and high ion/electron transport capability prepared by the three modification methods is introduced in lithium-ion capacitors.