A novel self-branching MnCo2O4/ nanographene hybrid composites on macroporous electrically conductive network as bifunctional electrodes for boosting miniature supercapacitors and sodium ion batteries

• Published in: Journal of alloys and compounds 2020-12, Vol.846, p.155720, Article 155720
• Main Authors: Wu, Dajun, Han, Haochi, Hong, Xuekun, Tao, Shi, Xu, Shaohui, Qian, Bin, Wang, Lianwei, Chen, Xuefeng, Chu, Paul K.
• Format: Article
• Language: English
• Subjects: Capacitance; Electrical resistivity; Electrodes; Electron conductivity; Energy storage; Flux density; Graphene; Hybrid composites; Ion transport; MnCo2O4; Nano composites; Nanographene; Particulate composites; Rechargeable batteries; Self-branching; Service life assessment; Sodium ion battery; Sodium-ion batteries; Supercapacitor; Supercapacitors; Three dimensional composites
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.155720

In situ construction of 3D MnCo2O4/graphene composites on a porous framework is a desirable means to improve charge storage and cycling lifetime of energy storage devices. Herein, a bifunctional MnCo2O4/nanographene hybrid composites (B-n-MnCo2O4) with novel self-branching construct are prepared on a macroporous electrically conductive network (MECN) for boosting miniature super-capacitors and sodium ion batteries. The porous B-n-MnCo2O4@MECN electrode provides adequate space to accommodate the large volume change and structural expansion during cycling. As a result, the 1 cm2 electrode boasts a capacitance of ∼7.02 F cm−2/∼2341 F g−1 at 3 mA cm−2. The B-n-MnCo2O4@MECN||AC@Ni-foam supercapacitor with a high energy density (32.0 Wh kg−1, at 6400 W kg−1) has a long lifetime as manifested by only 20% capacitance deterioration after 20,000 cycles. Meanwhile, as an anode in sodium-ion batteries (SIBs), B-n-MnCo2O4@MECN has a reversible specific capacity of 541.2 mAh g−1 at 50 mA g−1 and rate capability of 150.0 mAh g−1 at 200 mA g−1. Nanographene not only provides the conductive network for the self-branching MnCo2O4 to accelerate electron conductivity and ion transport, but also relieves the volume changes during cycling. The strategy and bifunctional materials have a large potential in different types of energy storage devices. [Display omitted] •A novel self-branching MnCo2O4/nanographene hybrid composites on MECN as functional electrodes are fabricated.•B-n-MnCo2O4@MECN with lots of active sites supports excellent electrochemical performance.•B-n-MnCo2O4@MECN.||AC@Ni-foam miniature supercapacitor develops the long lifetime and stability.•B-n-MnCo2O4@MECN as miniature sodium-ion batteries electrode has a reversible specific capacity of 541.2 mAh g−1 at 50 mA g−1.•Macroporous electrically conductive network (MECN) can prohibit the agglomeration of Mn-based spinel nanostructures.