Recent Advances of ZnCo2 O4 -based Anode Materials for Li-ion Batteries.

ZnCo2 O4 has been attracted wide research attention as a promising anode material for lithium-ion batteries (LIBs) in recent years based on its high theoretical specific capacity, low toxicity as well as stable chemical properties. However, the further large-scale application of pristine ZnCo2 O4 anode have been impeded because of its undesirable Li+ ion conductivity, low electronic conductivity, and finite stability of electrolytes at high potentials. Recently, optimizing the micro/nano structure, modification with carbonaceous materials, incorporation with metal oxides and constructing a binder-free structure on conductive substrate for ZnCo2 O4 -based materials have been verified as promising effective routes for solving the above problems. In this review, the recent advances in underlying reaction mechanisms, synthetic methods and strategies for improving the performance of ZnCo2 O4 anodes are comprehensively summarized. The factors affecting the electrochemical properties of ZnCo2 O4 -based materials are mainly discussed, and paths to promote the specific capacity and cyclic stability are proposed. Finally, several insights into the future developments, challenges, and prospects of ZnCo2 O4 -based anode materials of LIBs are proposed.

Synthesis and electrochemical properties of Zn2Ti3O8/g-C3N4 composites as anode materials for Li-ion batteries.

Zn2Ti3O8/g-C3N4 (0, 1, 3 and 8 wt%) composites were prepared via a simple solvothermal method, and their physical and electrochemical properties were systematically analyzed. SEM and HRTEM results show that the Zn2Ti3O8/g-C3N4 spherical structures with width sizes of about 500-700 nm are plump and uniform. Moreover, g-C3N4 with a large specific surface area can effectively buffer the deformation of Zn2Ti3O8 and reduce the resistance of Zn2Ti3O8 charge transfer and Li+ diffusion, thus improving the conductivity of Zn2Ti3O8. The results reveal that Zn2Ti3O8/g-C3N4 (3 wt%) had the most outstanding electrochemical performance of all samples. It can deliver discharge (charge) capacities of 444.6 (387.9), 284.5 (280.8), 197.5 (199.9), 149.9 (149.3), 119.2 (118.7) and 81.4 (81) mA h g-1 cycled at 50, 100, 300, 600, 900, and 1500 mA g-1, respectively. At the same current densities, pure Zn2Ti3O8 only provides discharge (charge) capacities of 325.4 (283.5), 223.7 (219.5), 142.9 (141.8), 95.4(94.8), 69.4 (69.4) and 38.3 (39.3) mA h g-1. The results verify that Zn2Ti3O8/g-C3N4 materials are expected to be remarkable anode materials for Li-ion batteries.