Assembly of MnO/CNC/rGO fibers from colloidal liquid crystal for flexible supercapacitors via a continuous one-process method

Flexible supercapacitors based on fiber shaped electrodes exhibit great potential for practical applications in smart fabrics owing to their light weight, good flexibility, and excellent weaveability. Herein, manganosite/carbonized cellulose nanocrystal/reduced graphene oxide (MnO/CNC/rGO) ternary composite fibers were fabricated from liquid crystal spinning dopes through a continuous one-process method. The assembly of CNC and manganese oxide nanoparticles in GO aqueous dispersion not only prevents GO nanosheets from restacking, but also ensures a uniform intercalation of nanoparticles. After a chemical and thermal reduction, the carbonized CNC contributes for additional electrical double layer capacitance while the MnO for faradaic pseudocapacitance. A fiber supercapacitor was assembled by arranging two MnO/CNC/rGO ternary composite fibers coated with PVA/H₃PO₄ gel electrolyte in parallel and it exhibited an energy density of 0.14 mWh cm^-3 at 4 mW cm^-3 and the maximum power density of 40 mW cm^-3. The fiber supercapacitor also demonstrated a good cycling stability (retains 82% of its initial capacitance after 6000 cycles) and bending robustness. This assembly approach is facile and scalable. More importantly the homogeneous dispersion of the nanoparticles in the ternary composite fibers shows promise for the future spreading of wearable electronic products.