Synthesis of ZnO–ZnCo₂O₄ hybrid hollow microspheres with excellent lithium storage properties

Graphical abstract: Display Omitted -- Highlights: • Well-dispersed ZnO–ZnCo₂O₄ hybrid hollow microspheres are prepared for the first time. • ZnO–ZnCo₂O₄ hybrid hollow microspheres exhibit greatly enhanced lithium storage properties. • The unique structural features of hybrid microspheres account for their superior electrochemical properties. -- Abstract: ZnO–ZnCo₂O₄ hybrid hollow microspheres are successfully produced via an annealing process of the pre-fabricated zinc–cobalt citrate hollow microspheres in air. ZnO and ZnCo₂O₄ have homogeneous distribution within the whole hollow microspheres. The gained hybrid hollow microspheres deliver outstanding lithium storage properties when utilized as the anode material in lithium ion batteries. A high reversible capacity of 1199 mA h g⁻¹ can be retained after 200 cycles. The exceptional electrochemical properties of the hybrid hollow microspheres are ascribed to the synergetic effect between ZnO and ZnCo₂O₄ nanoparticles, the catalytic effect of Co nanocrystals, the favorable hollow structures together with the nanometer-sized building blocks of hybrid microspheres