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CN-122025764-A - Li- (Y/Zr) -Cl-S solid electrolyte material co-doped with Mg, O and Br, and preparation and application thereof

CN122025764ACN 122025764 ACN122025764 ACN 122025764ACN-122025764-A

Abstract

The invention relates to the technical field of electrolyte materials, in particular to a Li- (Y/Zr) -Cl-S solid state electrolyte material co-doped with three elements of Mg, O and Br, which has an amorphous or microcrystalline structure, wherein the chemical composition general formula of the amorphous solid state electrolyte material is shown as Li a‑2k Mg k （Y x Zr 1‑x ） b S d‑z O z Cl c‑y Br y , wherein 0< x <1 >, a, b, c and d are stoichiometric numbers which balance charges of a matrix material, k is the doping amount of Mg, the doping amount of Mg replaces part Li+ in Mg2+ , z is the doping amount of O, O replaces part S2‑ in O2‑ , Y is the doping amount of Br, br replaces part Cl‑ in Br‑ , and compared with an undoped Li-Y/Zr-Cl-S matrix, the electrolyte material subjected to ternary co-doping modification of Mg, O and Br shows remarkable advantages in three aspects of ion conductivity, interface stability and environmental stability.

Inventors

  • WANG HUAPING
  • ZHANG MINGJU

Assignees

  • 广东栖川能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260307

Claims (10)

  1. 1. The Li- (Y/Zr) -Cl-S solid electrolyte material co-doped with three elements of Mg, O and Br is characterized in that the amorphous solid electrolyte material has an amorphous or microcrystalline structure, and the chemical composition general formula is shown as follows: Li a-2k Mg k （Y x Zr 1-x ） b S d-z O z Cl c-y Br y Wherein: 0≤x<1; a, b, c, d are stoichiometric numbers that allow charge balance of the matrix material, K is the doping amount of Mg, and part of Li + is replaced by Mg 2+ ; z is the doping amount of O, and O replaces part S 2- in the form of O 2- ; y is the doping amount of Br, which replaces part of Cl - in the form of Br - .
  2. 2. The Li- (Y/Zr) -Cl-S system solid electrolyte material co-doped with three elements of Mg, O, br according to claim 1, wherein the matrix composition of the amorphous solid electrolyte material is Li 7 （Y x Zr 1-x ）S 5 Cl and its derivatives.
  3. 3. The Li- (Y/Zr) -Cl-S system solid electrolyte material co-doped with three elements of Mg, O, br according to claim 1, wherein in the amorphous solid electrolyte material: The doping amount of Mg accounts for 0.05 at-0.5 at% of the total atomic number of the material; the substitution mole ratio of O satisfies the relation z/(d+z) =0.05-0.25; the molar ratio of Br satisfies the relation y/(c+y) =0.1 to 0.56.
  4. 4. The Li- (Y/Zr) -Cl-S system solid electrolyte material co-doped with three elements of Mg, O, br according to claim 1, wherein the crystal structure of the amorphous solid electrolyte material shows a broad peak around the diffraction angle of the matrix characteristic in the X-ray diffraction pattern, without precipitation of obvious impurity crystal phase.
  5. 5. The Li- (Y/Zr) -Cl-S solid electrolyte material co-doped with three elements of Mg, O and Br according to claim 1, wherein the lithium ion conductivity of the amorphous solid electrolyte material at 25 ℃ is 1.2×10 -2 ～1.8×10 -2 S/cm, and the ion migration activation energy is 0.18-0.26 ev.
  6. 6. A method for preparing the amorphous solid electrolyte material of the Li- (Y/Zr) -Cl-S system co-doped with three elements of Mg, O and Br according to any one of claims 1 to 5, which is characterized by comprising the following steps: Step 1, batching, namely weighing a lithium source, a zirconium source, an yttrium source, a sulfur source, a chlorine source, a bromine source, an oxygen source and a magnesium source precursor according to stoichiometric ratio in an inert atmosphere; step 2, ball milling and dispersing, namely ball milling the mixed precursor to uniformly disperse each element; And 3, heat treatment and quenching, namely heating the ball-milled powder to 300-600 ℃ in an inert atmosphere, preserving heat for 0.5-2 hours, and then rapidly quenching to room temperature to obtain the amorphous solid electrolyte material.
  7. 7. The preparation method of the Li- (Y/Zr) -Cl-S amorphous solid electrolyte co-doped with three elements including Mg, O and Br according to claim 6, wherein the ball milling condition is that ball milling is carried out under inert atmosphere, the ball milling temperature is less than or equal to-40 ℃, the ball milling rotating speed is 200-800 rpm, and the ball milling time is 12-60 hours.
  8. 8. The method for preparing the amorphous solid electrolyte of the Li- (Y/Zr) -Cl-S system, which is co-doped with three elements including Mg, O and Br, according to claim 6, wherein the lithium source is one or more selected from LiCl, liF, li 2 S、Li 2 O, liOH and LiBr, the yttrium source is one or more selected from YCl 3 , the zirconium source is one or more selected from ZrCl 4 , the chlorine source is one or more selected from LiCl, YCl 3 and ZrCl 4 , the fluorine source is one or more selected from LiF, the sulfur source is one or more selected from Li 2 S、ZrS 2 and MgS, the oxygen source is one or more selected from Li 2 O and/or LiOH, the magnesium source is one or more selected from MgCl 2 、MgBr 2 , mgO and MgS, and the bromine source is one or more selected from MgBr 2 and/or LiBr.
  9. 9. The method for preparing the Li- (Y/Zr) -Cl-S amorphous solid electrolyte co-doped with three elements including Mg, O and Br according to claim 6, wherein in the step 3, the temperature of the powder after ball milling is raised to 400-500 ℃ in an inert atmosphere, and the temperature is kept for 0.8-1.2 hours.
  10. 10. An all-solid lithium battery comprising a positive electrode, a negative electrode, and a solid electrolyte layer between the positive electrode and the negative electrode, the solid electrolyte layer comprising the amorphous solid electrolyte material of any one of claims 1-5.

Description

Li- (Y/Zr) -Cl-S solid electrolyte material co-doped with Mg, O and Br, and preparation and application thereof Technical Field The invention relates to the technical field of electrolyte materials, in particular to a Li- (Y/Zr) -Cl-S solid electrolyte material co-doped with three elements of Mg, O and Br, and preparation and application thereof. Background All-solid-state lithium ion batteries adopt nonflammable solid electrolyte, have high safety and high energy density potential, and are important directions for the development of next-generation lithium batteries. The conventional solid electrolyte mainly comprises two large systems of oxide and sulfide, wherein the oxide electrolyte has high chemical stability, low room-temperature ionic conductivity and high interface impedance with an electrode, and the sulfide electrolyte (such as Li 7P3S11、Li6PS5 Cl) has room-temperature ionic conductivity of 10 -2 S/cm and good interface contact, but has poor chemical stability, and exposed air is easy to react with water to generate toxic H 2 S gas. The halide electrolyte (such as Li 3YCl6、Li2ZrCl6) has a wide electrochemical stability window, is inert to air, has low raw material cost, and particularly Li 2ZrCl6 does not contain expensive and scarce elements, and has obvious cost advantage. However, the ionic conductivity of pure halides at room temperature is generally only 10 -4–10-3 S/cm, which is difficult to meet the requirement of high-power batteries, and the interface resistance is high when the pure halides are in direct contact with lithium metal, so that LiCl is easily generated by the degradation of the interface and the induction of lithium dendrites. To take advantage of both sulfide and halide, researchers have begun to try to develop a halide-sulfide mixed solid state electrolyte in combination with the two. For example, chinese patent CN115676883a discloses a Li-Zr-Cl-S system with room temperature ionic conductivity increased to 10 -3–10-2 S/cm, up to 4.34 x 10 -2 S/cm by optimizing the Li/Zr/Cl/S ratio. Another item CN115966756A discloses Li-Y-Cl-S systems with ionic conductivities exceeding 4X 10 -3 S/cm. These halide-sulfide electrolytes take advantage of the high mobility of the sulfide anions and the stable interfacial properties of the chloride anions, in part, to achieve both conductivity and stability. However, the materials still mainly use Cl - as halogen, li + is strongly bound in the crystal lattice, and ion migration kinetics are still in room for improvement. Meanwhile, the material has insufficient matching with a high-energy-density positive electrode (such as NMC 811) or a lithium negative electrode, and poor interface contact and side reaction can cause impedance increase to influence the multiplying power and the cycle performance of the battery. In addition, although the Li-Zr-Cl-S system does not contain P 2S5 which is easily hydrolyzed, it still reacts with trace amounts of moisture (such as Li 2S + H2O → H2 S) in air, is sensitive to environmental humidity, and needs to be prepared and used under low dew point conditions. Pure Li-Zr-Cl-S electrolyte was reported to have a mass gain of about 0.8% by placing it in dry air for 72 hours, H 2 S was detected at about 0.8ppm, and a mass gain of more than 3-5% by exposing it to air with a relative humidity of 50% for 24 hours, H 2 S concentration as high as several tens ppm, and macroscopic material decomposition occurred. Therefore, the ionic conductivity of the halide-sulfide electrolyte is further improved, the interface impedance is reduced, and the moisture resistance stability is improved on the premise of ensuring the environmental stability, so that the method is one of key problems to be solved in order to realize the high-performance all-solid-state battery. Therefore, we propose a Li- (Y/Zr) -Cl-S solid electrolyte material co-doped with three elements of Mg, O and Br, and its preparation and application for solving the above problems. Disclosure of Invention The invention aims to solve the defects in the prior art, and provides a Li- (Y/Zr) -Cl-S solid electrolyte material co-doped with three elements of Mg, O and Br, and preparation and application thereof. The solid electrolyte material of Li- (Y/Zr) -Cl-S system co-doped with three elements of Mg, O and Br has an amorphous or microcrystalline structure, and the chemical composition general formula is shown as follows: Lia-2kMgk（YxZr1-x）bSd-zOzClc-yBry Wherein: 0≤x<1; a, b, c, d are stoichiometric numbers that allow charge balance of the matrix material, K is the doping amount of Mg, and part of Li + is replaced by Mg 2+; z is the doping amount of O, and O replaces part S 2- in the form of O 2-; y is the doping amount of Br, which replaces part of Cl - in the form of Br -. Preferably, the matrix composition of the amorphous solid electrolyte material is Li 7（YxZr1-x）S5 Cl and derivatives thereof. Preferably, in the amorphous solid electrolyte material: The doping am