Chitosan modified graphene oxide with MnO2 deposition for high energy density flexible supercapacitors

• Published in: International journal of biological macromolecules 2024-02, Vol.259, p.129223-129223, Article 129223
• Main Authors: Zhang, Shouyun, Wang, Zhuoyu, Yang, Shuting, Hao, Dan, Yu, Shitao, Wu, Qiong
• Format: Article
• Language: English
• Subjects: Chitosan-based carbon; Flexible electrode; MnO2 deposition
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.129223

To obtain a flexible composite electrode material with excellent electrochemical performance, chitosan (CS)/graphene oxide (GO) composite pretreated from microwave hydrothermal is adopted as the carbon substrate, and MnO2 active material is uniformly deposited on their surface through anodic electrodeposition. In this composite system, CS penetrates into graphene sheets as small molecule units, forming NH-C=O groups with GO via dehydration condensation, which effectively inhibits the stacking of GO and improves the specific surface area, conductivity, as well as the wettability of the carbon support. MnO2 bonding with heteroatom N from CS enables high active material loadings and forms stable three-dimensional network structure, facilitating the enhanced electrochemical performance. Results indicate that increasing depositing MnO2 amount leads to more defective structures of the composite, which promotes their electrochemical performance when used as electrode material. The area specific capacitance of the optimal composite reaches 3553.74 mF/cm2 at 5 mA/cm2 in 1 M Na2SO4 electrolyte. Kinetic analysis shows the energy storage process is capacitance-dominated, with the redox reactions of MnO2 being the main contributor. The prepared asymmetric solid supercapacitor delivers an energy density high up to 0.585 mWh/cm2 at power density of 3000 mW/cm2, and their excellent flexibility makes them promising candidates as flexible sensor. •Flexible C/MnO2 electrodes with 3D network and high stability are constructed.•Chitosan enhances the linkage between MnO2 and carbon support.•GC-2/MnO2-20 with metal deposition loading of 50.8 mg exhibits the optimal properties.•Energy density high up to 0.585 mWh/cm2 is achieved for the asymmetric device.