Preparation And Performance Of Three-dimensional Ordered Macroporous ZnO/ZnS As Anode Materials For Lithium/Sodium Ion Batteries

The energy storage device has achieved great development in recent years since it can well overcome the drawback of the renewable energy that are restricted by the space and time and discontinuous supply of energy.As the current main energy storage system,the energy density of lithium/sodium ion batteries has become unable to satisfy the requirement.Thus designing and developing novel electrode materials with superior electrochemical performance are extremely meaningful for the development of the lithium/sodium ion batteries.ZnO/ZnS,as a kind of anode materials,owns high theoretical specific capacity that based on the conversion/alloy type reaction.However,the intrinsic low electrical conductivity and large volume expansion have severely impeded their practical application.In this research,the strategy of micro-nanostructure designing and self-supported electrode fabricating is adopted to improve the electrochemical performance of the ZnO/ZnS.In the first part,the modified colloidal crystal template method was employed to prepare the three-dimensional ordered macroporous ZnO directly the carbon cloth（3DOM ZnO/CC）as a free-standing anode for LIBs.Meanwhile,traditional powder3DOM ZnO were also fabricated via the colloidal crystal template method.The effect of the concentration and infiltration time of precursor sol on the 3DOM structure was explored,and the improvement effect of self-supported 3DOM structure on the electrochemical performance of ZnO was also studied.The results showed that the3DOM ZnO/CC could deliver a high areal capacity of 3.19 m Ah cm^-2(corresponding capacity is 773 m Ah g^-1 for the 3DOM ZnO)at the current density of 0.18 m A cm^-2after 100 cycles when tested as anode in LIBs.In the second part,the heterojunction of 3DOM ZnO/ZnS was prepared on the carbon cloth by colloidal crystal template method combined with the in-situ sulfurization.The positive effect of ZnO/ZnS heterojunction on electrochemical performance was studied and meanwhile the function mechanism was elaborately discussed.When tested as anode for sodium ion batteries,the 3DOM ZnO/ZnS/CC delivers a high reversible areal capacity of 1.44 m Ah cm^-2 at 0.26 m A cm^-2 even after100 cycles.When elevated to 2.6 m A cm^-2,it still maintains at 0.78 m Ah cm^-2.