Nickel-cobalt layered double hydroxide (NiCo-LDH) is a promising supercapacitor material, but its performance is limited by nanosheet stacking and poor conductivity. Incorporating a porous carbon support is an effective strategy to overcome these issues. Herein, porous carbon derived from both puffed and unpuffed sorghum seeds was synthesized at various pre-carbonization temperatures. The optimized carbon from puffed seeds (PH-R4A7), abundant in pyridinic-N and oxygen groups, facilitates the uniform growth of NiCo-LDH. The resulting NiCo-LDH/PH-R4A7 composite delivers a high specific capacitance of 807.2 C g− 1 at 1 A g− 1 and excellent capacitance retention (69.9% at 20 A g− 1), surpassing both pristine NiCo-LDH and its unpuffed counterpart (NiCo-LDH/PC-R4A7). Furthermore, an asymmetric supercapacitor (NiCo-LDH/PH-R4A7//PH-R6A7) achieves a high energy density of 85.1 Wh kg− 1 at a power density of 799.9 W kg− 1, along with outstanding cycling stability (88.4% capacitance retention after 10,000 cycles). This work demonstrates that puffing pretreatment is an important strategy for enhancing the structural and electrochemical properties of NiCo-LDH/ porous carbon composites.

Puffing pretreatment for sorghum seed-derived porous carbon in optimized NiCo-LDH growth and superior supercapacitor performance
    Abstract
    1 Introduction
    2 Experimental
        2.1 Chemical and materials
        2.2 Fabrication of puffed and unpuffed porous carbon materials
        2.3 Fabrication of NiCo-LDH/porous carbon composites
        2.4 Material characterization
        2.5 Electrochemical performance measurements
    3 Results and discussion
        3.1 Surface morphology analysis
        3.2 Structure and composition analysis
        3.3 Electrochemical performance analysis
    4 Conclusion
    References

• Ying Quan(School of Chemistry and Chemical Engineering, Henan Key Laboratory of Coal Green Conversion, Henan Polytechnic University, Jiaozuo 454000, China, Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Jiaozuo 454000, China)
• Yude Zhang(School of Chemistry and Chemical Engineering, Henan Key Laboratory of Coal Green Conversion, Henan Polytechnic University, Jiaozuo 454000, China, Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Jiaozuo 454000, China) Corresponding author
• Qian Zhang(School of Chemistry and Chemical Engineering, Henan Key Laboratory of Coal Green Conversion, Henan Polytechnic University, Jiaozuo 454000, China, Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Jiaozuo 454000, China) Corresponding author
• Yuanyuan Li(School of Chemistry and Chemical Engineering, Henan Key Laboratory of Coal Green Conversion, Henan Polytechnic University, Jiaozuo 454000, China)
• Mengjia Wang(School of Chemistry and Chemical Engineering, Henan Key Laboratory of Coal Green Conversion, Henan Polytechnic University, Jiaozuo 454000, China)
• Wenzhuo Cheng(School of Chemistry and Chemical Engineering, Henan Key Laboratory of Coal Green Conversion, Henan Polytechnic University, Jiaozuo 454000, China)