Reduced graphene oxide decorated CoSnO3@ZnSnO3 with multi-component double-layered hollow nanoboxes for high energy storage and capacity retention asymmetric supercapacitors

Double-layered hollow nanostructure composed of CoSn(OH)(6)@ZnSn(OH)(6) which are derived from CoSn(OH)(6) nanoboxes wrapped by ZnSn(OH)(6) cover layers is prepared by a controlled alkali etching method, followed by heating treatment to prepare reduced graphene oxide (rGO) decorated CoSnO3@ZnSnO3 nanoboxes. The results revealed that the specific surface area of CoSnO3@ZnSnO3 reached 70.29 m(2) g(-1), which is much higher than that of CoSnO3 (44.25 m(2) g(-1)). The enlargement in specific surface area of the double-layered hollow structure can responsible to provide sufficient buffer space for the dramatic volume change during the cycle. Moreover, rGO can effectively promote the transmission of ions or electrons and can provides a large reaction interface for electrochemical reaction. In addition, it can avoid CoSnO3@ZnSnO3 agglomeration and further improve storage capacity and stability. When the current density is 0.5 A g(-1), the capacitance of material is 400.2 F g(-1), which is higher than CoSnO3 and CoSnO3@ZnSnO3. Besides, the capacity retention rate of CoSnO3@ZnSnO3/rGO reaches 85% after 1100 cycles at a current density of 3 A g(-1). This work demonstrates the interaction between the modification of the rGO network and the multi-layered hollow structure with the high specific surface areas can provide large spaces to effectively buffer volume changes and facilitate electron and electrolyte ion transport. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

In this study, a double-layered hollow nanostructure composed of CoSn(OH)(6)@ZnSn(OH)(6) with rGO decoration was prepared by a controlled alkali etching method. The increased specific surface area of the double-layered hollow structure provided ample buffer space for volume changes during cycling, while rGO effectively facilitated ion and electron transport, leading to improved storage capacity and stability. The CoSnO3@ZnSnO3/rGO material exhibited higher capacitance and better capacity retention rate compared to CoSnO3 and CoSnO3@ZnSnO3, demonstrating the potential for high-performance energy storage applications.