Electrolyte additive, electrolyte and application in magnesium metal secondary battery

Abstract

The invention belongs to the technical field of batteries, and particularly relates to a functional electrolyte additive containing inorganic chloride, an electrolyte and application of the functional electrolyte additive in a magnesium metal secondary battery. The electrolyte additive is one or more of inorganic chlorides AClx shown in the specification, A is an element in IIIA, IVA or VA main groups, and the value of x is between 2 and 4. According to the invention, an in-situ chemical reaction between one or more specific inorganic metal chlorides in the electrolyte and magnesium metal is utilized to form a compact and stable protective solid electrolyte interface film (SEI film) on the surface of the magnesium metal negative electrode, so that further reaction between an additive, magnesium salt and the magnesium metal negative electrode is slowed down; and the interface compatibility between the electrolyte and the magnesium metal negative electrode is improved, so that the cycle performance of the magnesium metal secondary battery is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a functional electrolyte additive containing inorganic chloride, an electrolyte and its application in a magnesium metal secondary battery. Background technique [0002] In the post-lithium-ion battery era, magnesium metal secondary batteries have gradually attracted the attention of the industry, academia and research circles due to their high volumetric energy density, low cost, high safety, green environmental protection and many other advantages. In the magnesium metal secondary battery system, the use of magnesium metal anode is particularly critical because of its high volumetric specific capacity (3833mAh / cm 3 ), abundant resources, low cost, high intrinsic security and many other advantages. It should be said that compared with other secondary battery systems, the magnesium metal anode is the core technical advantage of the magnesium metal secondary battery...

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Problems solved by technology

However, recently, Banerjee et al. and Pint et al. have reported the uneven growth behavior of magnesium metal during the electrodeposition process, proving that magnesium metal anodes also have potential safety hazards of dendrite growth (Mater.Horiz., 2020, 7(3 ):843-854; Joule, 2020, 4(6):1324-1336)

In addition, the early studies on the magnesium electrolyte system all believed that once a passivation layer is formed on the surface of the magnesium metal negative electrode, it will hinder the formation of Mg. 2+ This is completely different from the mechanism by which the solid electrolyte interphase (SEI) is formed on the surface of the Li metal anode, and this characteristic imposes strict requirements on the reduction stability of the magnesium electrolyte components, which greatly limits the The optional range of magnesium electrolyte components is defined (BeilsteinJ. Nanotec., 2014, 5(1): 1291-1311)

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