Fe3O4/graphene-oxide/chitosan hybrid aerogel based high performance supercapacitor: effect of aqueous electrolytes on storage capacity & cell stability

In this work, Fe3O4/graphene-oxide/chitosan aerogel (GCFA) with 3-D interconnected structure (average pore size similar to 8.4 nm) and moderate BET surface area (similar to 59 m2/g) is synthesized by hydrothermal route. Three different hybrid symmetric supercapacitor cells are fabricated using GCFA as active electrode material, using basic (6M KOH: cell-1), acidic (1M H2SO4: cell-2), & neutral (Na2SO4: cell-3) as electrolyte mediums. Subsequently, a comprehensive study is carried out to assess the effect of electrolyte on the porous architecture, charge storage capacity, rate capability and cyclic stability. Besides, cell-3 also shows good cyclic stability with low initial fading (similar to 15%), good capacity retention (similar to 84%) It has been observed that cell-3 displayed better performance (specific capacitance similar to 160 F g 1, specific energy similar to 14.6 Wh kg 1 and specific power similar to 0.77 kW kg 1) than either of cell-2 (similar to 160 F g 1, similar to 7.84 Wh kg 1 and similar to 0.45 kW kg 1) or cell-1 (similar to 102 F g 1, similar to 1.54 Wh kg 1 and similar to 0.14 kW kg 1) and excellent coulombic efficiency (similar to 91%) even after 10,000 charge-discharge cycles. This is attributed to the better pore accessibility, stability of residual surface functionalities under potential cycling, and least screening for intra-pore shuttling of counter-ions under neutral medium.

Automated summary

A Fe3O4/graphene-oxide/chitosan aerogel with a 3D interconnected structure is synthesized and showed excellent performance as an active electrode material in a neutral electrolyte medium, with high specific capacitance, specific energy, and specific power, as well as good cyclic stability.