三维介孔钴酸锌立方体的制备及其优异的储锂性能

Synthesis and Lithium Storage Performance of Three-Dimensional Mesostructured ZnCo_2O_4 Cubes

采用简易、温和、实际耐用的水热方法制备了新型三维介孔立方体结构的钴酸锌纳米材料。每个钴酸锌立方体的边长大约在3-4μm之间,并由大量的纳米粒子和密集的孔隙所构成。通过氮吸附/脱附手段测试发现所制备的钴酸锌纳米材料具有较大的比表面积(41.4 m2?g^(-1))和介孔(6.32 nm)特性。使用钴酸锌纳米材料作为锂离子电池负极,金属锂作为正极组装锂电池并测试了材料的储锂性能。研究发现该电极材料在较高的电流密度下循环100周后,仍能呈现较高的可逆容量和超强的循环稳定性。这种优异的储锂性能主要归因于钴酸锌纳米材料的新型结构,这种介孔立方体结构能够加速锂离子的扩散,增加电极与电解液的接触面积并缓解锂离子嵌入/嵌出期间产生的体积膨胀。

Novel three-dimensional （3D） mesostructured ZnCo204 cubes are prepared through a convenient and practical hydrothermal route combined with an annealing treatment. The as-prepared ZnCo204 cubes range from 3-4 μm in size, and are composed of a large number of nanoparticles and pores. According to N2 adsorption-desorption measurements, the as-synthesized ZnCo2O4 cubes have a high BET surface area （41.4 m2.g-1） and mesoporous （6.32 nm） nature. Lithium ion batteries （LIBs） are assembled using the as-prepared ZnCo2O4 nanomaterial and metallic lithium as the anode and the cathode, respectively, and their lithium storage performance is investigated. The electrode material exhibits highly reversible lithium storage capacity and strong cycling stability at high current density for 100 cycles. More importantly, the ZnCo2O4 cube electrode still presents a relatively high specific capacity at high rate. The excellent lithium storage performance is attributed to the novel structure of the 3D mesostructured cubes, which can facilitate Li＋ diffusion, increase electrode/electrolyte contact area, and endure volume changes the during Li＋ insertion/extraction process.