Principles and applications of electrochemical capacitors

Kötz, R.; Carlen, Martin

doi:10.1016/s0013-4686(00)00354-6

Cited by 4,418 publications

(2,411 citation statements)

References 19 publications

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“…4,5 These charge transfer processes have been described as occurring at broadened equilibrium potentials that overlap to result in a nearly linear dependence of charge transferred (Q) versus applied potential (Φ), and thus a nearly constant capacitance ( ). 6 This electrochemical behavior mimics the rectangular-shaped cyclic voltammetry (CV) curves of double-layer or parallel-plate capacitors and is therefore termed "pseudocapacitance". Because electrochemical supercapacitor electrodes based on manganese dioxide (α-MnO 2 ) exhibit a high experimental specific capacity and are composed of low toxicity earth-abundant elements, they have become an attractive choice for commercialization.…”

Section: Introductionmentioning

confidence: 95%

Charge Storage in Cation Incorporated α-MnO₂

et al. 2015

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Electrochemical supercapacitors utilizing α-MnO 2 offer the possibility of both high power density and high energy density. Unfortunately, the mechanism of electrochemical charge storage in α-MnO 2 and the effect of operating conditions on the charge storage mechanism are generally not well understood. Here, we present the first detailed charge storage mechanism of α-MnO 2 and explain the capacity differences between α-and β-MnO 2 using a combined theoretical electrochemical and band structure analysis. We identify the importance of the band gap, work function, the point of zero charge, and the tunnel sizes of the electrode material, as well as the pH and stability window of the electrolyte in determining the viability of a given electrode material. The high capacity of α-MnO 2 results from cation induced charge-switching states in the band gap that overlap with the scanned potential allowed by the electrolyte. The charge-switching states originate from interstitial and substitutional cations (H + , Li + , Na + , and K + ) incorporated into the material. Interstitial cations are found to induce chargeswitching states by stabilizing Mn-O antibonding orbitals from the conduction band. Substitutional cations interact with O[2p] dangling bonds that are destabilized from the valence band by Mn vacancies to induce charge-switching states. We calculate the equilibrium electrochemical potentials at which these states are reduced and predict the effect of the electrochemical operating conditions on their contribution to charge storage. The mechanism and theoretical approach we report is general and can be used to computationally screen new materials for improved charge storage via ion incorporation.

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Section: Introductionmentioning

confidence: 95%

Charge Storage in Cation Incorporated α-MnO₂

et al. 2015

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“…However, problems arise due to the large polymers blocking the carbon pores during deposition, decreasing the surface area available for charge storage. Additionally, swelling and shrinking of the polymers may lead to decreased cyclic stability due to mechanical breakdown [8,48]. Coating the pore surfaces of high surface area carbon with a smaller nitrogen-containing molecule may alleviate these issues.…”

Section: Science China Materialsmentioning

confidence: 99%

Comparison of surface and bulk nitrogen modification in highly porous carbon for enhanced supercapacitors

Uchaker

2015

Sci. China Mater.

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“…The promising applications of RuO 2 range from electronic advancement in integrated circuit, film resistors, ferroelectric films to high-temperature superconducting thin films in forming a buffer layer [3][4][5]. The oxygen evolution reaction (OER) occurs at a suitable reaction rate on noble metals (e.g., Pt, Au, Ir, Ru and Ag), while metal oxides (RuO 2 and IrO 2 ) are generally more active electrocatalysts for this reaction than metal electrodes [6][7][8].…”

Section: Introductionmentioning

confidence: 99%