Transition metal selenide electrodes have attracted much attention in supercapacitor applications, due to their high electrical conductivity, superior electroactivity, and excellent structural stability. However, preparing the transition metal selenide with elaborate nanostructures remains a challenge. Herein, a two-step hydrothermal method was utilized to design NiCo₂Se₄ electrode with hollow nanotubes. By controlling the feeding of selenium in the selenization process, the formation mechanism of NiCo₂Se₄ nanotubes was investigated. In detail, the characterization methods, such as FESEM, TEM, XRD, EDS, and Raman spectroscopy, were implemented to study the influence of selenium on the morphology, structure composition, and electrochemical performance of NiCo₂Se₄ electrode. Moreover, an asymmetric supercapacitor was fabricated using the optimized NiCo₂Se₄ as positive electrode and activated carbon (AC) as negative electrode, showing high energy density of 25.0 Wh kg⁻¹ at a power density of 490 W kg⁻¹ and excellent cycle stability (93% of initial capacitance after 5000 cycles). This study will shed light on the facile design of transition metal selenide electrode with high electrochemical performance for supercapacitor applications.

过渡金属硒化物电极具有高电导率，优异的电活性和出色的结构稳定性，因此在超级电容器应用中引起了广泛关注。然而，制备具有精细纳米结构的过渡金属硒化物仍然是一个挑战。本文采用两步水热法设计了具有空心纳米管的NiCo ₂ Se ₄电极。通过控制硒化过程中硒的供给，NiCo ₂ Se ₄的形成机理研究了纳米管。详细地，通过FESEM，TEM，XRD，EDS和拉曼光谱等表征方法，研究了硒对NiCo ₂ Se ₄电极的形貌，结构组成和电化学性能的影响。此外，使用最优化的NiCo ₂ Se ₄作为正极并使用活性炭（AC）作为负极制造了不对称超级电容器，其在490 W kg ^-1的功率密度下显示出25.0 Wh kg ^-1的高能量密度。和出色的循环稳定性（5000次循环后初始电容的93％）。这项研究将为超级电容器应用提供具有高电化学性能的过渡金属硒化物电极的简便设计。