Self-supported binder-free carbon fibers/MnO2 electrodes derived from disposable bamboo chopsticks for high-performance supercapacitors

The increasing market growth of hybrid vehicles requires not only improvement on supercapacitor performance, but also cheap, abundant and sustainable material for supercapacitor fabrication. The present study demonstrated a novel strategy to convert used disposable bamboo chopsticks into uniform carbon fibers, and subsequently manganese dioxide (MnO2) was conformably grown on each fiber to form a carbon fiber/MnO2 composite. When it used as a self-supported binder-free electrode for supercapacitors, it delivered a superior mechanical stability, excellent rate capability, high specific capacitance of 375 F g−1 at the current density of 1 A g−1 and an increase specific capacitance was found after 5000 cycles interestingly. Moreover, the symmetric supercapacitor comprised of CFS/MnO2 electrodes presents a maximum energy density of 11 Wh kg−1 and a maximum power density of 17.4 kW kg−1. In addition, this approach presents a scalable, low-cost and sustainable route to transform chopsticks waste into carbon fibers to make electrodes for supercapacitors and lithium-ion capacitors.