Inorganic sulfide solid electrolyte and preparation method thereof

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to an inorganic sulfide solid electrolyte and a preparation method thereof, wherein the general formula of the inorganic sulfide electrolyte material is Li7+a-c(P1-aM'a)(S6-b-cM''b)Xc (I), wherein M' is one or more of Sn, Si, Al, Ge and Zr, M'' is one or more of Se, O and N, X is one or more of F, Cl, Br and I, a is larger than or equal to 0.01 and smaller than 1, b is larger than or equal to 0.01 and smaller than 5, c is larger than or equal to 0.7 and smaller than or equal to 1.5, and (b+c) is larger than (2.5a+1.5) and smaller than (1.5a+2.5). According to the electrolyte material disclosed by the invention, P and S sites are subjected to double-site substitution, and the sulfide solid-state electrolyte is high in ion conductivity and low in electron conductivity through the design of doping elements and a doping ratio, so that the use requirements of an all-solid-state battery are met; and the sulfide solid electrolyte is simple and effective in preparation method, low in production cost, relatively good in stability and high in lithium ion conductivity, and is expected to solve the practical application problem of an inorganic sulfide electrolyte serving as a high-performance all-solid-state lithium secondary battery electrolyte.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to an inorganic sulfide solid electrolyte and a preparation method thereof. Background technique [0002] Lithium-ion secondary batteries have developed rapidly due to their advantages such as high energy density and long service life since their commercialization. However, the currently widely used lithium-ion batteries are liquid-phase batteries, which contain flammable organic electrolytes, so there are serious safety hazards. In recent years, the occurrence of frequent safety accidents on liquid-phase lithium-ion power batteries has greatly restricted the further use of this system. The use of non-flammable inorganic solid materials as lithium-ion battery electrolytes can not only eliminate the safety hazards caused by the leakage of organic electrolytes during battery use and internal thermal runaway of batteries, but also can be used under extreme co...

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Problems solved by technology

Patent CN109526242A and patent CN109937507A report the doping of O and Se elements, but the doping sites of O and Se elements are the positions of halogens, and there is no further requirement on the doping ratio. Air stability is also not reported, and the electronic conductance reported by the two patents is higher (less than 10 -6 S / cm)

Patent CN108493479A reports a sulfide solid electrolyte containing metal oxides and individual non-metal oxides, which has certain air stability, but the doping method of metal / non-metal oxides limits the performance of sulfide solid electrolytes, resulting in sulfide The ion conductance of the solid electrolyte is low (0.25mS / cm)

And the patent CN108493479A does not report the doping position of each element in the metal / non-metal oxide

In addition, the above patents have not reported on the stability of Li metal anodes by simultaneously improving the sulfide solid electrolyte by doping.

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