Résumé
The undeniable benefit of lithium-ion (LIB) batteries for the development of a more environmentally friendly economy was recognized by the 2019 Nobel Prize in Chemistry. However, relying only on LIBs to energy storage will put considerable strain on lithium and cobalt resources used in these batteries. Therefore, alternative battery technologies other than LIBs are desirable to satisfy our growing demand for energy. Magnesium-ion batteries offer many distinct advantages over LIBs, including the high earth-abundance of magnesium, its high energy density and reversible dendrite-free Mg deposition
1
. In parallel, organic materials are receiving an increasing amount of attention as electrode materials for future post lithium-ion batteries due to their versatility and sustainability
2
. In order to propose organic cathode with both high potential and specific capacity, new polymer based on hydroquinone sulfide, poly(benzoquinone disulfide) (PBQDS), were prepared in view to be applied in both lithium and magnesium batteries. Diglyme and sulfolane solvents associated with both LiTFSI (lithium bistrifluomethane sulfonimide) and Mg(TFSI)
2
salts were selected, as electrolytes, in order to evaluate the potentiality of the active material
3
. First of all, the electrochemical responses of PBQDS in lithium and magnesium based electrolytes was performed in a cavity micro-electrode. Whereas in both case the cyclic voltammetry exhibit a close to reversible redox stem (Fig. 1a), The electrochemical characteristics of the material are very similar in term of potential and ΔE
peak
in both lithium and magnesium systems at a relative high scan rate i.e. 1 mV s
-1
. An improvement of the redox couple reversibility seems to be observed in Mg form, with a ΔE
peak
= 400 mV at E° of 0.3 V vs Fc
+
/Fc (3.5 vs Li
+
/Li). Given this interesting behavior, PBQDS in a coin cell configuration using glyme + LiTFSI electrolyte, was analyzed. . A stable capacity of 160 mAh g
-1
was obtained at C/10 after 70 cycles, whereas a value of 120 mAh g
-1
was maintained at C rate (Fig. 1b). In order to improve, the electrochemical performances, especially at high C-rate, the impact of the particle sizes (controlled grinding) of the cathodic material is in progress in view to approach its theoretical capacity value. In addition, the electrochemical investigations in both Mg and Li based electrolytes will be presented in regard to the electrolyte nature and the PBQDS morphology.
1. H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour, D. Aurbach, Energy Environ. Sci., 2013, 6, 2265–2279.
2. P. Poizot, F. Dolhem, Energy Environ. Sci., 2011, 4, 2003
3. H. Dong, Y. Liang, O. Tutusaus, R. Mohtadi, Y. Zhang, F. Hao, Y. Yao, Joule 2019, 3, 1–12
Figure 1