In-plane Vacancy-Induced Growth of Ultra-High Loading Cobalt Oxide-Graphene Composite for High-Performance Lithium-Ion Batteries

•Ultra-high loading cobalt oxide (93 wt%)/graphene composite has been successfully synthesized.•Graphene oxide with induced in-plane vacancies (deGO) is produced through acid-sonication pretreatment.•Ultra-high loading Co3O4 nanoparticles are in-situ grown onto deGO through a low-temperature hydrothermal reaction.•In-plane vacancies can induce the formation of Co3O4 NPs with an average particle size of ca. 10 nm.•Cobalt oxide-graphene composite exhibits a high reversible capacity, superior rate capability and much prolonged cycle life.

Ultra-high loading Co3O4 nanoparticles (NPs) with the particle size of ca. 10 nm anchoring on the acid-sonication pretreated graphene oxide with induced in-plane vacancies (deGO) are in-situ synthesized through a low-temperature hydrothermal reaction. These in-plane vacancies can act as active sites for the formation of Co3O4 NPs since Co2+ ions have a strong bonding effect with the carboxylate groups decorating the defect edge sites, in which nucleation, growth and crystallization of Co3O4 NPs are well separated and confined in a several nanometer region. Although the content is extremely low (7 wt%), deRGO can not only provide a support for anchoring Co3O4 NPs and work as a conductive matrix enabling good contact between them, but also prevent the particle aggregation and keep the integrity of the composite during long-term cycles. The as-prepared deRGO/Co3O4 anode exhibits a high specific capacity and superior rate performance with charge capacities of 727.1 mAh g−1 at 2 C, 559.4 mAh g−1 at 5 C and 70.45 mAh g−1 at 30 C. Meanwhile, no capacity fade can be observed after 100 cycles at 1 C, revealing a stable cycling ability. Therefore this material has great potential application for advanced Li-ion batteries.

Graphical abstractUltra-high loading Co3O4 nano-particles anchoring onto the acid-sonication pretreated graphene oxide with induced in-plane vacancies were applied as the high-performance lithium-ion anodes.Figure optionsDownload full-size imageDownload as PowerPoint slide