Three-dimensional ordered macroporous ZnO/ZnS heterostructure on carbon cloth as a free-standing anode with high areal capacity for sodium-ion batteries

As a promising alternative to the Lithium-ion batteries (LIBs), Sodium-ion batteries (SIBs) have drawn intensive attention due to their low cost. However, the limited areal capacity and cycle life of present sodium anode materials still largely impede their practical application. In order to obtain an excellent SIBs anode with high areal capacity, the three-dimensional ordered macroporous ZnO/ZnS heterostructure is directly fabricated on carbon cloth (3DOM ZnO/ZnS/CC) via a template method. From the perspective of materials designing, both the ZnO and ZnS own high specific capacity, meanwhile the ZnO/ZnS heterostructure can low the barrier energy and boost the charge transport. From the point of electrode engineering, the self-supported 3DOM structure can allow the complete penetration of electrolyte, shorten the ions diffusion path and enlarge the contact area between electrolyte and active materials, which are all beneficial for the mass transfer. As a result, the as-prepared electrode delivers a high reversible areal capacity of 1.44 mAh cm−2 at 0.26 mA cm−2 even after 100 cycles. When elevated to 2.6 mA cm−2, it still maintains at 0.78 mAh cm−2. This work provides a potential strategy of combining the materials designing and electrode engineering to fabricate the self-supported electrode with high performance for SIBs.