DataSheet2_Nano-architectured cobalt selenide spheres anchored on graphene oxide sheets for sodium ion battery anode.docx

Aimed at commercializing the technology of sodium-ion batteries (SIBs), researchers have been trying to produce electrode materials with optimally high charge storage capacity, superior rate capability, extended life, and cost-effective components. Herein, we synthesized an electrode of cobalt selenides loaded in carbon spheres and anchored on reduced graphene (CSSs@rGO) for high-performance SIBs. This improved structure of CSSs@rGO permits the pseudocapacitive storage of charge, thus enhancing the electrical characteristics. It was discovered that the diameter of the carbon sphere had a significant impact on the charge storage capacities of the developed electrode materials, suggesting the probable depth of sodium-ion (Na-ion) movement in the electrode materials during charge and discharge. For instance, CSSs@rGO with an average diameter of ∼70 nm presented the best electrochemical performance as an anode of SIBs. The nano-architecture CSSs@rGO exhibits excellent ion storage capability with a reversible capacity of 600 mA h g-1 at a discharge rate of 100 mA g−1 after 50 cycles. However, at a higher discharge rate (e.g., 1,000 mA g−1), a storage capacity as high as 380 mA h g−1 was achieved. In addition to higher charge storage capability and efficient charge storage at higher discharge rates, the developed CSSs@rGO exhibited stable cycling performance for over 3,000 cycles, which clearly shows the feasibility of our products. This work will open new approaches for developing advanced electrode materials for high-performance sodium-ion batteries.

为推动钠离子电池（Sodium-ion Batteries, SIBs）技术的商业化应用，科研人员一直致力于开发兼具最优高储电容量、优异倍率性能、更长循环寿命以及低成本组分的电极材料。本研究中，我们合成了一种负载硒化钴、锚定于还原氧化石墨烯的碳球电极（CSSs@rGO），用于高性能钠离子电池。该CSSs@rGO的优化结构可实现赝电容储电，从而提升电极的电学特性。研究发现，碳球直径对所制备电极材料的储电容量具有显著影响，这暗示了充放电过程中钠离子（Na-ion）在电极材料内部的迁移深度。例如，平均直径约为70 nm的CSSs@rGO作为钠离子电池负极时，展现出最优的电化学性能。该纳米结构CSSs@rGO具备优异的离子储纳能力：在100 mA·g⁻¹的放电倍率下循环50圈后，可逆容量可达600 mA·h·g⁻¹。而在更高的放电倍率（如1000 mA·g⁻¹）下，其储电容量仍可达到380 mA·h·g⁻¹。除了具备更高的储电容量以及在高倍率下高效储电的特性外，所制备的CSSs@rGO还展现出超过3000圈的稳定循环性能，这充分证明了该材料的应用可行性。本研究为开发高性能钠离子电池用先进电极材料开辟了新的技术路径。