Elevating the comprehensive performance of carbon-based hybrid electrode materials by incorporating nickel silicate for lithium-ion capacitors

Abstract

Lithium-ion capacitors (LICs) are gaining increasing research interest due to their combination of the advantages of lithium-ion batteries and supercapacitors. Carbon–metal oxide/hydroxide hybrid materials show great potential as anode materials for LICs, but their specific capacity still needs further improvement to meet future requirements. In this study, a method of incorporating nickel silicate into carbon–metal oxide/hydroxide hybrid materials is recommended to improve their overall lithium-ion storage performance. This method is easily achieved using silicon oxide-containing bamboo leaf-derived carbon (BLC) as a raw material. A novel nickel hydroxide-nickel silicate-carbon hybrid material (NiSiC) can be obtained via the reaction between BLC and nickel nitrate. When employed as a lithium-ion energy storage electrode material, NiSiC exhibits a significantly higher specific capacity and retained capacity after the cycling test, in contrast to BLC, due to the contribution of nickel-based hybrid materials. Of utmost importance, the nickel silicate component of NiSiC is capable of reducing charge transfer resistance, suppressing electrode volume expansion, and introducing silicon to contribute extra capacity. Consequently, compared to a nickel hydroxide-carbon hybrid material (NiC) lacking the nickel silicate component, NiSiC demonstrates remarkable improvements in rate performance, cycling performance, and specific capacity performance. Owing to the excellent performance of NiSiC, a LIC utilizing NiSiC as the anode material demonstrates excellent lithium storage performance and practical application capabilities.