The ternary transitional metal oxide NiCo₂O₄ is a promising anode material for sodium ion batteries (SIBs) due to its high theoretical capacity and superior electrical conductivity. However, its sodium storage capability is severely limited by the sluggish sodiation/desodiation reaction kinetics. Herein, NiCo₂O₄ double-shelled hollow spheres were synthesized via a microwave-assisted, fast solvothermal synthetic procedure in a mixture of isopropanol and glycerol, followed by annealing. Isopropanol played a vital role in the precipitation of nickel and cobalt, and the shrinkage of the glycerol quasi-emulsion under heat treatment was responsible for the formation of the double-shelled nanostructure. The as-synthesized product was tested as an anode material in a sodium ion battery, and was found to exhibit a high reversible specific capacity of 511 mAh g^-1 at 100 mA g^-1 and deliver high capacity retention after 100 cycles. 

三元过渡金属氧化物NiCo ₂ O ₄具有较高的理论容量和优异的导电性，因此是用于钠离子电池（SIB）的有希望的阳极材料。然而，其钠存储能力受到缓慢的磺化/脱氧反应动力学的严格限制。在此，NiCo ₂ O ₄通过微波辅助的快速溶剂热合成方法，在异丙醇和甘油的混合物中合成双壳空心球，然后进行退火。异丙醇在镍和钴的沉淀中起着至关重要的作用，并且在热处理条件下甘油准乳液的收缩是形成双壳纳米结构的原因。合成后的产品作为钠离子电池中的负极材料进行测试，发现在100 mA g ^-1时显示出511 mAh g ^-1的高可逆比容量，并在100次循环后提供了高容量保持率。