Biowaste-Derived Three-Dimensional Porous Network Carbon and Bioseparator for High-Performance Asymmetric Supercapacitor

To explore renewable resources and reduce pollution, the common biowaste eggshell membrane (ESM) is utilized for electrode materials and separators in asymmetric supercapacitor. This device includes air-activated ESM carbon as the negative electrode, MnO2 nanoparticle/chemical-activated ESM carbon as the positive electrode, and natural ESM as the separator, achieving a high energy density of 14 W h kg–1 along with acceptable power density of 150 W kg–1 and cycling stability (79% capacitance retention after 1000 cycles). Significantly, the air-activated ESM carbon achieves a superior specific capacitance of 478.5 F g–1 in 1.0 M Na2SO4, and the natural ESM based bioseparator displays an impressive ion conductivity and cycling stability. This work demonstrates an operable way to reuse the common biowaste for renewable energy devices with high performance.