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 ∼8.4 nm) and moderate BET surface area (∼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 (∼15%), good capacity retention (∼84%) It has been observed that cell-3 displayed better performance (specific capacitance ∼160 F g⁻¹, specific energy∼14.6 Wh kg⁻¹ and specific power∼0.77 kW kg⁻¹) than either of cell-2 (∼160 F g⁻¹, ∼7.84 Wh kg⁻¹ and ∼0.45 kW kg⁻¹) or cell-1 (∼102 F g⁻¹, ∼1.54 Wh kg⁻¹ and ∼0.14 kW kg⁻¹) and excellent coulombic efficiency (∼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.