CN-122025762-A - Lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte and preparation method thereof

Abstract

The invention relates to the technical field of battery preparation, and provides a lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte and a preparation method thereof, wherein the main components of the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte are as follows The lithium oxide concentration gradient exists along the thickness direction of the electrolyte, the molar content of the surface lithium oxide is 5-15%, and the molar content of the center lithium oxide is 0.5-3%, wherein x is more than or equal to 0.05 and less than or equal to 0.8,0.01 and y is more than or equal to 0.3. The lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte can avoid stress concentration caused by concentration mutation and inhibit interface layering risk and longitudinal penetration of lithium dendrites by arranging the lithium oxide gradient along the thickness direction of the electrolyte.

Inventors

• ZHU FAJUN
• CHEN XIAOBO
• ZHANG WEIMIN

Assignees

• 广州广花博粤新能源有限公司

Dates

Publication Date

20260512

Application Date

20260225

Claims (10)

1. 1. A lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte is characterized in that the main component of the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte is A lithium oxide concentration gradient exists along the thickness direction of the electrolyte, the molar content of the surface layer lithium oxide is 5-15%, and the molar content of the central layer lithium oxide is 0.5-3%; Wherein, the x is more than or equal to 0.05 and less than or equal to 0.8,0.01 y is more than or equal to 0.3.
2. 2. The lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid state electrolyte of claim 1, wherein the lithium oxide concentration decays exponentially from the surface layer to the center to avoid abrupt interface stresses of linear gradients.
3. 3. The lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid state electrolyte of claim 2 wherein said lithium oxide concentration is a function of concentration ; Wherein, the Respectively represents the surface layer lithium oxide molar concentration and the center layer lithium oxide molar concentration of the solid electrolyte, Respectively represent normalized thickness coordinates and concentration peak shift factors, Representing the steep factor of the gradient, Representing the position Lithium oxide concentration at the site.
4. 4. A method for preparing a lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte, which is characterized by being used for preparing the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte according to any one of claims 1-3.
5. 5. The method for preparing the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte as claimed in claim 4, wherein the preparation method comprises the steps of hot-press molding the surface layer of the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte, and sintering the inner core layer of the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte.
6. 6. The method for preparing the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte as claimed in claim 5, wherein the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte is 280 percent -350 Hot-press forming the surface layer of the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte at a low temperature, and at 450 -Sintering the inner core layer of the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid state electrolyte at a high temperature of 550 ℃ to form a concentration gradient structure.
7. 7. The method for preparing the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte as claimed in claim 6, which comprises the following steps: acquiring a basic oxygen doping amount and an oxygen doping activation threshold; According to the basic oxygen doping amount, the oxygen doping activation threshold and the position The lithium oxide concentration at the position is used for constructing an effective oxygen doping amount model; and obtaining the effective oxygen doping amount according to the effective oxygen doping amount model.
8. 8. The method for preparing the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte as claimed in claim 7, wherein the preparation method further comprises the following steps: acquiring low-temperature sintering activation energy, high-temperature sintering activation energy and hot pressing pressure; Constructing a dual-activation-energy sintering dynamics model according to the low-temperature sintering activation energy, the high-temperature sintering activation energy and the hot pressing pressure; and obtaining densification rate according to the dual activation energy sintering dynamics model.
9. 9. The method for preparing a lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte as claimed in claim 8, wherein the dual activation energy sintering dynamics model is expressed as ; Wherein, the Respectively represents the activation energy of low-temperature sintering, the activation energy of high-temperature sintering and the hot pressing pressure, Respectively representing ideal gas constant, absolute temperature and pressure sensitivity index, A, B representing low temperature process dynamics factor and high temperature process dynamics factor, Indicating the densification rate.
10. 10. The method for preparing a lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte as claimed in claim 9, wherein the hot pressing pressure is between 30MPa and 100 MPa.

Description

Lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte and preparation method thereof Technical Field The invention relates to the technical field of battery preparation, in particular to a lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte and a preparation method thereof. Background The lithium phosphorus sulfur chlorine electrolyte is generally composed of lithium salt (such as LiCl), phosphorus sulfur compound (such as P2S 5) and doping elements, forms a glassy or crystalline structure, is a sulfide solid electrolyte, belongs to a core material of an all-solid lithium battery, and has high ionic conductivity and good mechanical ductility. As one of the sulfide electrolytes most studied in recent years, lithium phosphosulfide chlorosulfide (LPSC) has high ion conductivity and relatively low cost, but has disadvantages of poor stability and poor compatibility of positive and negative electrode materials, etc., which limit its practical application. In order to improve the performance, researchers often prepare the composite solid electrolyte through polymer modification (such as PEO, PMMA and the like) so as to improve interface contact and electrochemical stability, and aim to improve the interface compatibility and electrochemical stability of LPSC. Despite the challenges, LPSC is still one of the hot directions of research for all-solid batteries due to its high ion conductivity and low cost advantages. The existing Li6PS5Cl system is easy to generate side reaction with lithium metal to generate a high-impedance interface phase (such as Li2S, P S X), so that interface resistance is increased and dendrite penetration is caused, and a core contradiction between high ion conductivity and interface instability exists. Disclosure of Invention Based on the above, in order to inhibit the longitudinal penetration of lithium dendrites, the invention provides a lithium phosphorus sulfur chlorine oxygen solid electrolyte doped with lithium oxide gradient and a preparation method thereof, and the specific technical scheme is as follows: a lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte comprises the main components of A lithium oxide concentration gradient exists along the thickness direction of the electrolyte, the molar content of the surface layer lithium oxide is 5-15%, and the molar content of the central layer lithium oxide is 0.5-3%; Wherein, the x is more than or equal to 0.05 and less than or equal to 0.8,0.01 y is more than or equal to 0.3. The lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte can avoid stress concentration caused by concentration mutation and inhibit interface layering risk and longitudinal penetration of lithium dendrites by arranging the lithium oxide gradient along the thickness direction of the electrolyte. Preferably, the lithium oxide concentration decays exponentially from the surface layer to the center to avoid abrupt interface stresses of linear gradients. Preferably, the lithium oxide concentration is a function of the concentration distribution; Wherein, the Respectively represents the surface layer lithium oxide molar concentration and the center layer lithium oxide molar concentration of the solid electrolyte,Respectively represent normalized thickness coordinates and concentration peak shift factors,Representing the steep factor of the gradient,Representing the positionLithium oxide concentration at the site. A preparation method of lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte is used for preparing the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte. Preferably, the preparation method comprises the steps of hot-press molding the surface layer of the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte, and sintering the inner core layer of the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte. Preferably, at 280-350Hot-press forming the surface layer of the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid electrolyte at a low temperature, and at 450-Sintering the inner core layer of the lithium oxide gradient doped lithium phosphorus sulfur chlorine oxygen solid state electrolyte at a high temperature of 550 ℃ to form a concentration gradient structure. Preferably, the preparation method comprises the following steps: acquiring a basic oxygen doping amount and an oxygen doping activation threshold; According to the basic oxygen doping amount, the oxygen doping activation threshold and the position The lithium oxide concentration at the position is used for constructing an effective oxygen doping amount model; and obtaining the effective oxygen doping amount according to the effective oxygen doping amount model. Preferably, the preparatio