Interface engineering for enhancing performance of additive-free NiTe@NiCoSe2 core/shell nanostructure for asymmetric supercapacitors

Abstract

Interface engineering of electro-active materials for supercapacitor (SC) is an effective strategy to adjust their corresponding physic-chemical properties. In this article, the core/shell structured NiTe@NiCoSe2 composite with a 3D hierarchical architecture has been reasonably defined by coating large theoretical capacity NiCoSe2 on NiTe nanorods using a simple hydrothermal method followed by electrodeposition process. Density functional theory (DFT) calculations indicate that the NiTe@NiCoSe2 sample has an enhanced density of state (DOS) near the Fermi level, which provide additional theoretical assistance for the improved electrochemical performance. Thanks to the well-designed core/shell architecture and high-efficient synergistic effects among multi-components, the prepared NiTe@NiCoSe2 electrode exhibits excellent energy storage capability. In addition, the NiTe@NiCoSe2//AC asymmetric supercapacitor (ASC) delivers a maximum energy density of 59.8 Wh kg−1 at 800 W kg−1. Importantly, the outstanding durableness with 96.6% capacitance retention after 10000 cycles manifests the good stability of the core/shell structure of the NiTe@NiCoSe2 electrode. These superior electrochemical performances show that the current composite materials are comparable to the most Se/Te-based electrodes for supercapacitors.