In Situ Solid-Phase Synthesis of CoZnSe/CNT Nanocomposites for High-Performance Sodium-Ion Energy Storage Devices

The development of effective strategies to accelerate the diffusion kinetics of Na⁺ ions and improve the cycle stability of electrode materials is crucial for high-performance sodium-ion energy storage devices. In this article, we present a one-step in situ solid-phase synthesis method for preparing CoZnSe/CNT nanocomposites to address the inherent defects of traditional solid-phase synthesis methods. The three-dimensional (3D) framework constructed from CNTs provides a highly conductive substance, enabling the formation of CoZnSe/CNT nanocomposites with high conductivity, fast Na⁺ diffusion kinetics, and excellent cycle stability, ensuring good performance in both sodium-ion batteries and hybrid supercapacitors. The synthesized CoZnSe/CNT nanocomposite delivers a high reversible specific capacity of 433.14 mAh g^–1 at 0.1 A g^–1 and 280.3 mAh g^–1 at 5.0 A g^–1 when applied in a sodium-ion half-cell device. The assembled sodium-ion hybrid supercapacitor device shows a long cycle life and high capacity retention even at high current density. A high energy density of 152.96 Wh kg^–1 can be delivered at a power density of 2.16 kW kg^–1 with 70.4 Wh kg^–1 delivered even at a high power density of 36 kW kg^–1. A capacity retention rate of more than 79.61% is achieved after 6000 cycles at 1 A g^–1. The CoZnSe/CNT nanocomposite prepared by the proposed method exhibits excellent performance in sodium-ion energy storage devices, comparable to that achieved by liquid-phase synthesis methods, demonstrating its significant advantages and promising application prospects for the synthesis of high-performance sodium-ion energy storage materials.