Reduced graphite oxide wrapped ZnO-SnO2 hollow nanospheres with as anodes for hybrid high energy density supercapacitors

• Published in: Diamond and related materials Vol. 136; p. 110076
• Main Authors: Li, Xiaoqin, Zhou, Lingling, Zhao, Shanhai, Ding, Hao, Cao, Haijing, Fang, Zebo, Jiang, Feng, Li, Huiyu, Liu, Yongsheng, Zhu, Yanyan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2023
• Subjects: Bimetallic oxide; pseudo-capacitors; Supercapacitors; Bimetallic oxide; Supercapacitors; pseudo-capacitors
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2023.110076

As cathode materials for supercapacitors, metallic oxide composites have high theoretical capacities, which have received widespread attentions. However, due to the rapid capacity degradation，it remains a challenge to the development of metallic oxides. A composite electrode material for supercapacitors scheme is proposed in this paper, which is constructed by novel hybrid ZnO-SnO2 nanoparticles, annealed from hollow nanospheres ZnSn(OH)6, and is well encapsulated within a three-dimensional reduced graphene oxide (RGO). The RGO@ZnO-SnO2 electrodes show excellent performances with high initial coulomb efficiency of 98.9 %, high reversible capacities (581.8 F g−1 at 0.5 A g−1), enhanced long-term cycling with capacity retention rate of 98 % and fantastic rate capability (440.9 F g−1 at 5A g−1) after 1000 cycles. When assembled with AC cathodes, the full supercapacitors exhibit excellent electrochemical performances (26 Wh·kg−1 at 0.75 kW·kg−1, 8.2 W·kg−1 at 9.87 kW·kg−1). This method also provides a new idea for the preparation of other bimetallic selenides, oxides, sulfides or phosphides with improved electrochemical properties. [Display omitted] •The conductivity of ZnO-SnO2 is significantly improved by compositing with RGO.•Hollow ZnO-SnO2 particles alleviate volume expansion during charge-discharge.•The large specific surface area makes RGO@ZnO-SnO2 have a high specific capacity of 581.8F.g−1 at 0.5A.g−1.•Assembled asymmetric supercapacitors retain 97.1 % capacity after 7000 cycles.