Incorporation of pseudocapacitive materials into porous carbon is a promising strategy to boost electrochemical performance. Herein, composite of biomass-derived porous carbon and MnO2 (a typical pseudocapacitive material) was facilely fabricated through an in-situ synthesis approach with sorghum seeds derived porous carbon (SSC) as the skeleton for MnO2 deposition. The as-prepared composite ( MnO2@SSC) exhibits hierarchical porous structure with abundant interlaced MnO2 nanowires wrapping on the surface. While the porous structure is beneficial to the active sites exposure and electrolyte ions transport, the interlaced three-dimensional (3D) network of MnO2 nanowires significantly boosts the tolerance toward volume shrinkage/expansion during the cyclic process. Consequently, the MnO2@ SSC-based electrode delivered quite promising supercapacitive performance including superior specific capacitance of 482.7 F/g at 0.5 A/g, outstanding long-term cycling stability (95.8% specific capacitance retention after 20,000 cycles) and high energy density of 13.7 Wh/kg at power density of 298.1 W/kg. Furthermore, all-solid-state flexible supercapacitor based on MnO2@ SSC can be facilely bent to various angles (0° to 150°) without significant degradation in the capacitive performance. This study provides a facile, cost-effective, and sustainable approach for the fabrication of high-performance electrode materials.

MnO2 nanowires anchored on biomass-derived porous carbon for enhanced supercapacitive performance
    Abstract
    1 Introduction
    2 Experimental section
        2.1 Preparation of sorghum seeds (SS) derived porous carbon (SSC)
        2.2 Growth of MnO2 nanowire on porous carbon (MnO2@SSC)
        2.3 Electrochemical measurements
    3 Results and discussion
    4 Conclusions
    5 Supplementary information
    Acknowledgements 
    References

• Tao Feng(Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan 430205, China)
• Yufan Mo(Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan 430205, China)
• Bowei Zou(Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan 430205, China)
• Chunhui Zhang(Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan 430205, China)
• Hui Chen(Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan 430205, China)
• Gang Liu(Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan 430205, China) Corresponding author