Redox mediator induced electrochemical reactions at the electrode‐electrolyte interface: Making sodium‐ion supercapacitors a competitive technology

Abstract

The specific capacitance values of Na-ion supercapacitor can now compete with other well-established pseudocapacitors. This is obtained by using redox additive modified electrolytes in combination with hierarchical nanostructures of NaMnPO 4 . Modifying the conventionally used electrolyte, that is: NaOH, with redox additives such as potassium ferricyanide [K 3 Fe(CN) 6 ] and potassium iodide (KI), can induce nearly 50% enhancement in the specific capacitance. The enhancement is also retained in full cell, fabricated using NaMnPO 4 and activated carbon as the positive and negative electrodes, respectively. Redox mediators stimulate extra redox pairs and higher ionic conductivity, leading to enhanced electrochemical reactions at the electrode-electrolyte interface.

Pseudo 2-dimensional nanostructures of metal oxides for high-performance supercapacitors

“…Again, the active site directly depends on the surface area of the coated material. The voltammetric charge ( q *) was calculated using the following equation: 42 where, s , I , V and A denote the scan rate, voltammetric current (mA), potential (mV) and geometric area of the electrode (cm 2 ), respectively. Additionally, q * can be expressed as: q * = q 0 + s −1/2 where, q 0 is the charge measured by the double layer and s is the scan rate.…”

“…Again, the active site directly depends on the surface area of the coated material. The voltammetric charge (q*) was calculated using the following equation: 42 qà ¼…”

2D material-based sensing devices: an update

“…However, not all analytes can induce redox reactions, and thus external mediators are necessary to generate electrochemical signals proportional to the analyte concentration. 186 Consequently, a specic working electrode design modied with 2D materials can improve the quantitative measurement of electrochemical signals during a particular analyte-antigen interaction. 187,188 In electrochemical sensing devices, the primary detection mechanism involves the transfer of electrons from the active material deposited/coated on the working electrode in a trielectrode functional structure immersed in an electrolyticcontaining solution.…”

“…However, not all analytes can induce redox reactions, and thus external mediators are necessary to generate electrochemical signals proportional to the analyte concentration. 186 Consequently, a specific working electrode design modified with 2D materials can improve the quantitative measurement of electrochemical signals during a particular analyte-antigen interaction. 187,188…”

Organic Supercapacitors as the Next Generation Energy Storage Device: Emergence, Opportunity, and Challenges

“…), neutral (KCl, Na 2 SO 4 , etc. ), polymeric, ionic liquid, etc [44–46] . Among these some of them are aqueous and some are non‐aqueous.…”