Magnesium batteries: a study of self-discharge and heat generation

There has long been an interest in magnesium batteries as an alternative to lithium-ion batteries due to their substantial abundance, cheaper, and sustainability. The interaction between Mg2+ and electrolyte solutions and cathode materials causes slow ion dissociation and diffusion, leading to low power output. Despite still under development, magnesium-ion batteries have the potential to compete with lithium-ion batteries in terms of volumetric and specific capacities. Mo6S8 (chevrel phase), 1,4-polyanthraquinone (14PAQ), and 1,5-polyanthraquinone (15PAQ) cathode materials-based coin cells are assembled against Mg-foil as an anode by using 0.3M Mg[B(hfip)4]2 /DME, 0.5M Mg[B(hfip)4]2 /DME and 0.5M Mg[B(hfip)4]2.3DME in tetraglyme electrolytes. The chevrel phase (CP) was found to be more suitable in respect of heat generation. Nevertheless, the specific capacity is comparatively lower than organic-based cathode materials. It is equally important for battery kinetics to have a well-designed electrolyte, therefore different solvents with the same conductive salt are utilized. The noticeable differences are observed and in tetraglyme solvent stable cyclic and fewer self-discharge phenomena are observed. ... mehrHowever, the activation process needs a more cyclic procedure to achieve the required capacity. The generated heat during cycling phases indicated the high resistances, swelling/contraction in organic cathode yielding in higher heat generation and poor capacity retention. To overcome self-discharging in Mg batteries, detailed side reactions/dissolution of electrode and interfaces investigation on the anode side must be considered as Mg(OH)2, MgF, MgO are the common interfaces.