Electrochemical Insertion of Magnesium in Metal Oxides and Sulfides from Aprotic Electrolytes

Abstract

The electrochemistry of TiS2 , ZrS2 , RuO2 , Co3O4 , and V2O5 has been studied in several organic solvents containing normalMgfalse(ClO4)2 in view of their application as positive electrodes in rechargeable magnesium batteries. Only V2O5 showed promising coulombic capacity and reversibility. Mg2+ insertion into this oxide depends on the ratio between the amounts of H2O and Mg2+ as well as on the absolute amount of H2O in the electrolyte. Water molecules preferentially solvating Mg2+ions appear to facilitate the insertion process. The highest coulombic capacities of up to 170 Ah/kg were reached in acetonitrile solutions containing 1M normalMgfalse(ClO4)2+1M H2O .

The Influence of Intercalated Ions on Cyclic Stability of V2o5/Graphite Composite in Aqueous Electrolytic Solutions: Experimental and Theoretical Approach

“…5). On the other hand, in spite the strong interaction of Mg 2+ ions with the host structure and a probability that highly solvated Mg 2+ ion can participate in intercalation [18,28], the best cyclic stability of V 2 O 5 xerogel/ graphite composite was observed during insertion/deinsertion of the smallest Mg 2+ ions (Fig. 6).…”

“…The Na + -and Mg 2+ -ion rechargeable batteries are extensively studied as a real alternative [1][2][3][4][5][6][7][8], thanks primarily to a higher abundance and better environmental friendliness of these elements. V 2 O 5 has been intensively studied as the electrode material due to its high energy density [5,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Apart of efficient insertion/ deinsertion of Li + ions [11,[12][13][14], V 2 O 5 displayed capability of reversible insertion of both Na + [15][16][17] and Mg 2+ ions [18][19][20][21].…”

“…V 2 O 5 has been intensively studied as the electrode material due to its high energy density [5,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Apart of efficient insertion/ deinsertion of Li + ions [11,[12][13][14], V 2 O 5 displayed capability of reversible insertion of both Na + [15][16][17] and Mg 2+ ions [18][19][20][21]. Numerous examinations of electrochemical properties of V 2 O 5 , focused preferably to the organic electrolytes, revealed that both capacity and cyclic stability of this compound depend on its exact chemical composition, crystal structure and crystallinity [16,[22][23][24][25].…”

“…The main obstacle to its use presented a low mobility of Mg 2+ ions in solids, and formation of solid electrolyte interface (SEI) at the electrode/organic electrolyte boundary, being a great barrier for diffusion of Mg 2+ ions [19,20,28]. Novak and Desilvestro [18] tried to solve these problems by adding water to organic electrolyte, in order to hydrate the Mg 2+ ions. In this way, they succeeded to improve the insertion/deinsertion capability of V 2 O 5 toward Mg 2+ ions but the cyclic stability remained a weak point.…”

High Energy Density Electrode Materials for Rechargeable Magnesium Batteries

“…Traditional cathode materials include oxides based on molybdenum, cobalt, manganese, and vanadium. Meanwhile, other candidates such as MgxMnSiO4, TiS2 and sulfur are also being investigated as cathode materials for Mg batteries (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). Besides aiming at improving primary battery characteristics such as voltage, capacity and cycle life, the biggest challenge to develop suitable cathode materials for Mg batteries is to overcome the slow kinetics caused by the divalent Mg 2+ ions and maintain high Mg 2+ mobility.…”