Oxygen‐Vacancy Abundant Ultrafine Co3O4/Graphene Composites for High‐Rate Supercapacitor Electrodes

The metal oxides/graphene composites are one of the most promising supercapacitors (SCs) electrode materials. However, rational synthesis of such electrode materials with controllable conductivity and electrochemical activity is the topical challenge for high‐performance SCs. Here, the Co3O4/graphen...

Full description

Saved in:
Bibliographic Details
Published in:Advanced science 2018-04, Vol.5 (4), p.1700659-n/a
Main Authors: Yang, Shuhua, Liu, Yuanyue, Hao, Yufeng, Yang, Xiaopeng, Goddard, William A., Zhang, Xiao Li, Cao, Bingqiang
Format: Article
Language:English
Subjects:
graphene
laser irradiation
oxygen vacancies
supercapacitors
ultrafine Co3O4 nanoparticles
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The metal oxides/graphene composites are one of the most promising supercapacitors (SCs) electrode materials. However, rational synthesis of such electrode materials with controllable conductivity and electrochemical activity is the topical challenge for high‐performance SCs. Here, the Co3O4/graphene composite is taken as a typical example and develops a novel/universal one‐step laser irradiation method that overcomes all these challenges and obtains the oxygen‐vacancy abundant ultrafine Co3O4 nanoparticles/graphene (UCNG) composites with high SCs performance. First‐principles calculations show that the surface oxygen vacancies can facilitate the electrochemical charge transfer by creating midgap electronic states. The specific capacitance of the UCNG electrode reaches 978.1 F g−1 (135.8 mA h g−1) at the current densities of 1 A g−1 and retains a high capacitance retention of 916.5 F g−1 (127.3 mA h g−1) even at current density up to 10 A g−1, showing remarkable rate capability (more than 93.7% capacitance retention). Additionally, 99.3% of the initial capacitance is maintained after consecutive 20 000 cycles, demonstrating enhanced cycling stability. Moreover, this proposed laser‐assisted growth strategy is demonstrated to be universal for other metal oxide/graphene composites with tuned electrical conductivity and electrochemical activity. A novel one‐step laser irradiation route through simultaneous laser‐induced reduction and fragmentation to prepare ultrafine Co3O4 nanoparticles/graphene (UCNG) composites is proposed for the first time. Because of the plentiful oxygen vacancies on the ultrafine Co3O4 nanoparticles surface and the tightly anchoring of Co3O4 nanoparticles on graphene, the UCNG composites exhibit outstanding electrochemical performance, especially for high‐rate capability (93.7%).
ISSN:2198-3844
2198-3844
DOI:10.1002/advs.201700659