A kind of lithium supplement additive and preparation method thereof

Abstract

The invention discloses a lithium-supplementing additive and a preparation method thereof. The lithium-supplementing additive is a powdery particle with median size D50 greater than or equal to 0.1mu m and smaller than or equal to 30mu m, and a chemical formula is xLi2O yM zNmXn, wherein y is greater than 0, z is greater than 0, and 2x-y-z*m is greater than 0.1; M is selected from one or multiple of Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper) and Cr (chromium), and the valence state of M is 0; N is selected from one or multiple of Mn, Fe, Co, Ni, Cu, Al (aluminum), Ti (titanium), Zn (zinc), Cr, Sn (stannum), Si (silicon) and Mg (magnesium); X is selected from one or multiple of O (oxygen), OH, F (fluorine), PaOb, BaOb, SO4 and CO3. The lithium-supplementing additive has the advantages that more stability and safety are realized; in the initial charging process, a lithium source can be provided to compensate the consumption of lithium when an SEI (solid electrolyte interphase) film is formed by a cathode and an anode, the initial charging and discharging efficiency, cycle property, discharging capacity and energy density are improved, and the lithium-supplementing additive is especially suitable for a cathode system with lower initial charging and discharging efficiency.

Description

technical field The invention relates to the technical field of lithium ion secondary batteries, in particular to a lithium supplementing additive and a preparation method thereof. Background technique Lithium-ion secondary batteries have the advantages of high voltage and high energy density, and are widely used in the power supply of consumer electronic products, energy storage systems, and power systems. Improving the energy density of lithium-ion batteries has always been the most concerned by the industry and academia. question. During the first charging process of the battery, a surface solid electrolyte film (SEI film) is formed on the surface of the positive and negative electrodes, which will consume lithium and irreversibly solidify the lithium into lithium carbonate or alkoxide, ester salt, etc., resulting in reversible lithium loss, reduce first-time efficiency, and reduce battery discharge capacity. Especially when some high-capacity new negative active mater...

AI Technical Summary

Problems solved by technology

When using lithium metal, the requirement for the dryness of the environment is high. Powdered lithium metal has a very high reactivity, is flammable, and is easy to splash. It is difficult to manufacture and process. Lithium metal may remain inside the battery, which may bring potential dangers in subsequent use. ;When using organolithium solution, the danger brought by the powder can be avoided, but organolithium is often more active, and often needs to be protected by an inert atmosphere during the manufacturing process and cannot be manufactured and processed in the air, and is also very sensitive to moisture. Difficult to be compatible with existing processes

Images