Transition metal oxides are expected to replace commercial graphite for the next generation of secondary battery anode materials. However, the capacity decreases rapidly due to poor conductivity and volume expansion during operation. In this study, we first designed a yolk-shell structured ZnCo₂O₄ sphere, and then combined it with reduced graphene oxide through an electrostatic interaction process. The prepared ZnCo₂O₄/RGO showed enhanced lithium/sodium storage performance. Specifically, it can provide 997.2 mA h g⁻¹ (for LIBs, 500 cycles) and 280 mA h g⁻¹ (for SIBs,1000 cycles) reversible capacities at 1.0 A g⁻¹ current density, respectively. These superior properties are derived from their unique structure. On the one hand, the gap between the yolk and shells not only provides a shorter Li⁺/Na⁺ diffusion distance, but also the electrolyte can be in sufficient contact with the anode material to induce a rapid surface reaction; on the other hand, the introduction of graphene can effectively buffer the large volume expansion of the cycle and maintain the structural integrity of the electrode material.

过渡金属氧化物有望替代商用石墨，用于下一代二次电池负极材料。但是，由于操作过程中导电性和体积膨胀差，容量迅速降低。在这项研究中，我们首先设计了卵黄壳结构的ZnCo ₂ O ₄球，然后通过静电相互作用过程将其与还原的氧化石墨烯结合。制备的ZnCo ₂ O ₄ / RGO显示出增强的锂/钠存储性能。具体来说，它可以在1.0 A g ^-1下提供997.2 mA h g ^-1（对于LIB，500个周期）和280 mA h g ^-1（对于SIB，1000个周期）可逆容量。电流密度。这些优越的性能源于其独特的结构。一方面，蛋黄和壳之间的间隙不仅提供了更短的Li ⁺ / Na ⁺扩散距离，而且电解质可以与阳极材料充分接触，从而引起快速的表面反应。另一方面，石墨烯的引入可以有效地缓冲循环的大体积膨胀并保持电极材料的结构完整性。