Understanding of carbon-based supercapacitors ageing mechanisms by electrochemical and analytical methods

Yinghui Liu (1, 2, 3) , Benoît Soucaze-Guillous (1) , Pierre-Louis Taberna (2, 3) , Patrice Simon (2)

1 Technocentre Renault [Guyancourt]
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
3 RS2E - Réseau sur le stockage électrochimique de l'énergie

In order to shed light on ageing mechanisms of Electrochemical Double Layer Capacitor (EDLC), two kinds of activated carbons are studied in tetraethyl ammonium tetrafluoroborate (Et4NBF4) in acetonitrile. In floating mode, it turns out that two different ageing mechanisms are observed, depending on the activated carbon electrode materials used. On one hand, carbon A exhibits a continuous capacitance and series resistance fall-off; on the other hand, for carbon B, only the series resistance degrades after ageing while the capacitance keeps unchanged. Additional electrochemical characterizations (Electrochemical Impedance Spectroscopy e EIS e and diffusion coefficient calculations) were carried out showing that carbon A's ageing behavior is suspected to be primarily related to the carbon degradation while for carbon B a passivation occurs leading to the formation of a Solid Electrolyte Interphase-Like (SEI-L) film. These hypotheses are supported by TG-IR and Raman spectroscopy analysis. The outcome forms the latter is an increase of carbon defects on carbon A on positive electrode

Mots clés: Supercapacitor ageing; Electrochemical characterization; Diffusion coefficient; Activated carbon corrosion; Ageing mechanism

Domaines: Matériaux; Matériaux

Yinghui Liu, Benoît Soucaze-Guillous, Pierre-Louis Taberna, Patrice Simon. Understanding of carbon-based supercapacitors ageing mechanisms by electrochemical and analytical methods. Journal of Power Sources, 2017, 366, pp.123-130. ⟨10.1016/j.jpowsour.2017.08.104⟩. ⟨hal-01687184⟩