A three-dimensional flower-like NiCo₂S₄ formed by two-dimensional nanosheets is synthesized by a facile hydrothermal method and utilized as the anode for sodium-ion batteries. Studies have shown that materials can achieve the best performance under the ether-based electrolyte system with voltage ranging from 0.3 to 3 V, which could effectively avoid the dissolution of polysulfides and over-discharge of the material. Here, sodium storage mechanism and charge compensation behaviors of this ternary metal sulfide are comprehensively investigated by ex situ X-ray diffraction. Moreover, ex situ Raman spectra, ex situ X-ray photoelectron spectroscopy and transmission electron microscopy measurements are used to related tests for the first time. Additionally, quantitative kinetic analysis unravels that sodium storage partially depends on the pseudocapacitance mechanism, resulting in good specific capacity and excellent rate performance. The initial discharge capacity is as high as 748 mAh·g⁻¹ at a current density of 0.1 A·g⁻¹ with the initial coulomb efficiency of 94%, and the capacity can still maintain at 580 mAh·g⁻¹ with the Coulomb efficiency close to 100% after following 50 cycles. Moreover, by the long cycle test at a high current density of 2 A·g⁻¹, the capacity can still reach at 376 mAh·g⁻¹ after over 500 cycles.

通过简便的水热法合成由二维纳米片形成的三维花状NiCo ₂ S ₄，并将其用作钠离子电池的负极。研究表明，在以醚为基础的电解质体系中，材料的电压范围为0.3至3 V，可以达到最佳性能，这可以有效避免多硫化物的溶解和材料的过放电。在此，通过异位X射线衍射全面研究了该三元金属硫化物的钠存储机理和电荷补偿行为。此外，非原位拉曼光谱，非原位X射线光电子能谱和透射电子显微镜测量首次用于相关测试。此外，定量动力学分析揭示了钠存储部分取决于拟电容机制，从而导致良好的比容量和出色的速率性能。在0.1 A·g ^-1的电流密度下，初始放电容量高达748 mAh·g ^-1，初始库仑效率为94％，而使用库仑时，放电容量仍可保持在580 mAh·g ^-1。经过50个循环后，效率接近100％。此外，通过在2 A的高电流密度的长周期测试·克^-1，容量仍可达到在376毫安·克^-1后超过500个循环。