Rational design of walnut-like ZnO/Co3O4 porous nanospheres with substantially enhanced lithium storage performance.

Rational fabrication and smart design of multi-component anode materials to achieve desirable reversible capacities and exceptional cyclability are significant for lithium-ion batteries (LIBs). Herein, walnut-like ZnO/Co3O4 porous nanospheres were prepared by a facile solvothermal method, which were then applied as a mechanically stable anode material for LIBs. The rationally designed hybridized electrode brings favorable structural features, particularly ZnO/Co3O4 porous nanospheres with abundant vacant space and enhanced surface area, enhancing lithium/electron transport and relieving volumetric stresses during the cycling process. Moreover, several in situ hybridized anode materials with electrochemical cooperation further overcome the challenge of capacity decay and conductivity deficiency. The as-obtained ZnO/Co3O4 delivered a much better lithium storage performance compared with ZnO, Co3O4, and their physical mix. We believe that the novel design criteria will bring opportunities in exploration and promote the practical application of transition metal oxides.

Calcination-Free Synthesis of Well-Dispersed and Sub-10†nm Spinel Ferrite Nanoparticles as High-Performance Anode Materials for Lithium-Ion Batteries: A Case Study of CoFe2 O4.

Spinel ferrites are promising anode materials for lithium-ion batteries (LIBs) owing to their high theoretical specific capacities. However, their practical application is impeded by inherent low conductivity and severe volume expansion, which can be surpassed by increasing the surface-to-volume ratio of nanoparticles. Currently, most methods produce spinel ferrite nanoparticles with large size and severe aggregation, degrading their electrochemical performance. In this study, a low-temperature aminolytic route was designed to synthesize sub-10 nm CoFe2 O4 nanoparticles with good dispersion through carefully exploiting the reaction of acetates and oleylamine. The performance of CoFe2 O4 nanoparticles obtained by a traditional co-precipitation method was also investigated for comparison. This work demonstrates that CoFe2 O4 nanoparticles synthesized by the aminolytic route are promising as anode materials for LIBs. Besides, this method can be extended to design other spinel ferrites for energy storage devices with superior performance by simply changing the starting material, such as MnFe2 O4 , MgFe2 O4 , ZnFe2 O4 , and so on.