Advances in core-shell nanostructures for high performance supercapacitors

Abstract

The growing global energy demand necessitates advanced energy storage devices with high power density, fast charge-discharge ability, long cycling life, and mechanical flexibility. Supercapacitors address these needs, but their relatively low energy density still limits wider applications. Core-shell structured materials have emerged as promising electrodes for next-generation supercapacitors due to their hierarchical designs, which offer high surface area, abundant redox-active sites, and efficient ion/electron transport. The interaction between the core and shell helps prevent structural damage during continuous charge-discharge cycles. Diverse materials including carbon nanostructures, transition metal oxides, double layer hydroxides, conducting polymers, sulfides, nitrides, metal-organic framework (MOF)-derived hybrids, etc. have been engineered into core-shell configurations to associate complementary properties such as high conductivity and enhanced redox activity. Different synthetic techniques allow fine tuning of core-shell structures, ensuring optimized morphology, composition, and ultimately enhanced charge-storage behavior. As a result, significant improvements in capacitance and rate capability have been achieved. These improvement in performance and durability also motivates for the development of flexible and all-solid-state supercapacitors. However, challenges remain in scalable production of high-energy materials with long-term cycling stability and device-level integration. Continued innovation in rational design is crucial for realizing core-shell electrodes into high-performance supercapacitors for energy storage applications.