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EP-4266444-B1 - SOLID ELECTROLYTE, METHOD FOR PREPARING SAME, AND ALL-SOLID-STATE BATTERY COMPRISING SAME

EP4266444B1EP 4266444 B1EP4266444 B1EP 4266444B1EP-4266444-B1

Inventors

  • KWON, Ohmin
  • MOON, JI WOONG
  • NAM, SANG CHEOL
  • PARK, YONG SUN

Dates

Publication Date
20260506
Application Date
20211214

Claims (9)

  1. A solid electrolyte, comprising: a sulfur compound represented by Chemical Formula 1 below and contains B in an amount of 10 ppm to 100,000 ppm. [Chemical Formula 1] Li 7-x PS 6-x Cl 1-y Br y (In the Chemical Formula 1, 1 < x < 2, 0 ≤ y < 1)
  2. The solid electrolyte of claim 1, wherein: the solid electrolyte is represented by Chemical Formula 2. [Chemical Formula 2] Li 7-x PS 6-x B z Cl 1-y Br y O 3/2z (In the Chemical Formula 2, 1 < x < 2, 0 ≤ y < 1, and 0 < z ≤ 0.5)
  3. The solid electrolyte of claim 1, wherein: the B content is 1,000ppm to 100,000ppm.
  4. The solid electrolyte of claim 1, wherein: the solid electrolyte is of the argyrodite type.
  5. A manufacturing method for a solid electrolyte according to claim 1, comprising: preparing a mixture by mixing a compound containing lithium-containing sulfide, P and S-containing sulfide, Cl-containing compound and B-containing compound; producing a pellet by compressing the mixture; and heat treating the pellet, wherein, the B-containing compound is H 3 BO 3 , Li 3 BO 3 , BBr 3 , BCl 3 or a combination thereof.
  6. The method of claim 5, wherein: the mixing is carried out at a speed of 100 rpm to 2,000 rpm.
  7. The method of claim 5, wherein: the compression is carried out under a pressure of 100MPa to 500MPa.
  8. The method of claim 5, wherein: the heat treatment process is carried out at 400°C to 600°C.
  9. An all solid-state battery comprising: a negative electrode; a positive electrode; and a solid electrolyte of any one of claim 1 to claim 4, positioned between the negative electrode and the positive electrode.

Description

Field of the Invention Solid electrolyte, its manufacturing methods, and solid-state batteries containing it. Description of the Related Art Recently, with the rapid spread of electronic devices using batteries such as IT mobile devices and small power-driven devices (e-bikes, small EVs, etc.), the demand for small, lightweight, and relatively high-capacity lithium secondary batteries is rapidly increasing. As the demand for lithium secondary batteries explodes, safety issues are emerging as a major issue. In order to improve safety and energy density among lithium secondary batteries, all-solid-state batteries are receiving a lot of attention. This all-solid-state battery is a battery in which all materials are solid, and refers to a battery that uses a particularly solid electrolyte. This all-solid-state battery has excellent safety with no risk of leakage of electrolyte solution, and has the merit of being easy to manufacture thin batteries. As the solid electrolyte, sulfide-based solid electrolytes with the composition as Li6PS5Cl with an argyrodite structure are mainly researched. However, these sulfide-based solid electrolytes are difficult to handle in a general atmosphere due to a reaction with moisture. KR 101 952 196 B1 describes the preparation of a solid electrolyte by solid state reaction; a compound of formula Li6.13P0.8Si0.15S4.7O0.3Cl is mentioned. SUMMARY OF THE INVENTION One embodiment is to provide a solid electrolyte that can improve water stability without deteriorating ion conductivity and battery performance. Another embodiment is to provide a manufacturing method of the solid electrolyte. Another embodiment is to provide an all-solid-state battery including the solid electrolyte. One embodiment provides a solid electrolyte, comprising: a sulfur compound represented by Chemical Formula 1 below and contains B in an amount of 10 ppm to 100,000 ppm.         [Chemical Formula 1]     Li7-xPS6-xCl1-yBry (In the Chemical Formula 1, 1 < x < 2, 0 ≤ y < 1) The solid electrolyte is represented by Chemical Formula 2.         [Chemical Formula 2]     Li7-xPS6-xBzCl1-yBryO3/2z (In the Chemical Formula 2, 1 < x < 2, 0 ≤ y < 1, and 0 < z ≤ 0.5). The B content is 1,000ppm to 100,000ppm. The solid electrolyte is of the argyrodite type. Another embodiment provides a manufacturing method for solid electrolyte, comprising: preparing a mixture by mixing a compound containing lithium-containing sulfide, P and S-containing sulfide, Cl-containing compound and B-containing compound; producing a pellet by compressing the mixture; and heat treating the pellet, wherein, the B-containing compound is H3BO3, Li3BO3, BBr3, BCl3 or a combination thereof. The mixing is carried out at a speed of 100 rpm to 2,000 rpm. The compression is carried out under a pressure of 100MPa to 500MPa. The heat treatment process is carried out at 400°C to 600°C. Another embodiment provides an all-solid-state battery including a negative electrode positive electrode and the solid electrolyte positioned between the negative electrode and the positive electrode. The solid electrolyte according to one embodiment can exhibit excellent output characteristic and cycle-life characteristic of the all-solid battery. DETAILED DESCRIPTION OF THE EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of claims described later. Unless otherwise stated in this specification, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In addition, unless otherwise specified, % means wt%, and 1ppm is 0.0001 wt%. The solid electrolyte according to one embodiment may include a compound represented by Chemical Formula 1 below.         [Chemical Formula 1]     Li7-xPS6-xCl1-yBry (In the Chemical Formula 1, 1 < x < 2, 0 ≤ y < 1) The solid electrolyte contains B, wherein the B content may be 10 ppm to 100,000 ppm, or 1,000 ppm to 100,000 ppm. When the B content is included in the range, it is possible to reduce the amount of H2S gas generated during charging and discharging of the all-solid-state battery using the same, and to improve the cycle-life characteristic. As such, the solid electrolyte containing B may be expressed by Chemical Formula 2 below.         [Chemical Formula 2]     Li7-xPS6-xBzCl1-yBryOz3/2z (In the Chemical Formula 2, 1 < x < 2, 0 ≤ y < 1, and 0 < z ≤ 0.5) As such, the solid electrolyte according to one embodiment is an argyrodite-type solid electrolyte, and as one containing B, moisture safety can be improved without deterioration of ion conductivity and battery performance according to B content. This is considered to be because B serves as a sintering material and oxygen supply material. If, i