IP Library › Granted Patent US 12,555,819
Granted Patent B2
US 12,555,819 · App. 17/898,550 · Granted Feb 17, 2026

Thermal energy storage with phase change materials having an adjustable transition temperature

Inventors: Ravi Prasher (Danville, CA); Sumanjeet Kaur (Pinole, CA); Gao Liu (Piedmont, CA); Christopher Dames (Berkeley, CA); Jonathan Lau (Fremont, CA); Drew Lilley (Berkeley, CA); Piyachai Khomein (San Bruno, CA); Joseph Papp (Martinez, CA)
Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
H01M10/056H01M4/364H01M4/485H01M4/583H01M4/608H01M10/052H01M50/417H01M50/426H01M50/46H01M2004/027H01M2004/028
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Quick Facts
Patent No.
US 12,555,819
App. No.
17/898,550
Granted
Feb 17, 2026
Kind
B2
Abstract

This disclosure provides systems, methods, and apparatus related to thermal energy storage with phase change materials having an adjustable transition temperature. In one aspect, a method includes providing a device. The devices includes a phase change material, a salt dissolved in the phase change material, and an anode and a cathode disposed in the phase change material. The phase change material changes from a solid to a liquid at a first temperature when the salt is dissolved in the phase change material. A voltage is applied to the anode and the cathode to substantially remove the salt from the phase change material. The phase change material changes from the solid to the liquid at a second temperature when the salt is substantially removed from the phase change material, with the first temperature being a lower temperature than the second temperature.

Claims (43)

1 . A method comprising:

providing a device, the device comprising:

a phase change material,

a salt dissolved in the phase change material, the phase change material changing from a solid to a liquid at a first temperature when the salt is dissolved in the phase change material, and

an anode and a cathode disposed in the phase change material;

applying a voltage to the anode and the cathode to substantially remove the salt from the phase change material, the phase change material changing from the solid to the liquid at a second temperature when the salt is substantially removed from the phase change material, the first temperature being a lower temperature than the second temperature.

2 . The method of claim 1 , further comprising:

removing the voltage from the anode and the cathode to dissolve the salt in the phase change material, the phase change material changing from the solid to the liquid at the first temperature when the salt is dissolved in the phase change material.

3 . The method of claim 1 , wherein the salt is dissolved in the phase change material when the device is in a first ambient temperature, wherein the salt is substantially removed from the phase change material when the device is in a second ambient temperature, and wherein the first ambient temperature is a lower temperature than the second ambient temperature.

4 . The method of claim 3 , wherein the first ambient temperature occurs at night time, and wherein the second ambient temperature occurs at day time.

5 . The method of claim 3 , wherein the first ambient temperature occurs in winter time, and wherein the second ambient temperature occurs in summer time.

6 . The method of claim 1 , wherein when the voltage is applied to the anode and the cathode, cations of the salt are incorporated into the anode and anions of the salt are incorporated into the cathode.

7 . The method of claim 1 , wherein the voltage applied to the anode and the cathode is about 2.5 volts (V) or less.

8 . The method of claim 1 , wherein the phase change material comprises poly(ethylene glycol) (PEG).

9 . The method of claim 1 , wherein the salt is a lithium salt.

10 . The method of claim 1 , wherein the salt is a lithium salt from a group of lithium oxalatodifluoroborate (LiODFB), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium iodide (LiI), cesium bis(trifluoromethanesulfonyl)imide (CsTFSI), and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide-PEG (Pyr 14 TFSI-PEG).

11 . The method of claim 1 , wherein a concentration of the salt in the phase change material when the salt is dissolved in the phase change material is about 5 mol % to 50 mol %.

12 . The method of claim 1 , wherein the anode comprises lithium titanium oxide (Li 4 Ti 5 O 12 , LTO).

13 . The method of claim 1 , wherein the cathode comprises a material from a group of a composite of a polyaniline (PANI) conductive polymeric material and carbon black and a composite of poly(3,4-ethylenedioxythiophene) (PEDOT) and carbon nanotubes.

14 . The method of claim 1 , wherein the device further comprises:

a separator between the anode and the cathode.

15 . The method of claim 14 , wherein the separator comprises a polymer separator.

16 . The method of claim 14 , wherein the separator cis a separator selected from a group of a polypropylene separator and a polyvinylidene fluoride (PVDF) separator.

17 . The method of claim 1 , wherein the device is a thermal energy storage device.

18 . A device comprising

a phase change material, a salt being dissolved in the phase change material, the phase change material operable to change from a solid to a liquid at a first temperature when the salt is dissolved in the phase change material; and

an anode and a cathode disposed in the phase change material, and when a voltage is applied to the anode and the cathode, the salt is substantially removed from the phase change material, the phase change material changing from the solid to the liquid at a second temperature when the salt is substantially removed from the phase change material, and the first temperature being a lower temperature than the second temperature.

19 . The device of claim 18 , further comprising:

a separator disposed between the anode and the cathode.

20 . The device of claim 19 , wherein the separator comprises a polymer separator.

21 . The device of claim 19 , wherein the separator is a separator selected from a group of a polypropylene separator and a polyvinylidene fluoride (PVDF) separator.

22 . The device of claim 18 , wherein the phase change material comprises poly (ethylene glycol) (PEG).

23 . The device of claim 18 , wherein the salt is a lithium salt.

24 . The device of claim 18 , wherein the salt is a lithium salt from a group of lithium oxalatodifluoroborate (LiODFB), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium iodide (LiI), cesium bis (trifluoromethanesulfonyl) imide (CsTFSI), and 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide-PEG (Pyr 14 TFSI-PEG).

25 . The device of claim 18 , wherein a concentration of the salt in the phase change material when the salt is dissolved in the phase change material is about 5 mol % to 50 mol %.

26 . The device of claim 18 , wherein the anode comprises lithium titanium oxide (Li 4 Ti 15 O 12 , LTO).

27 . The device of claim 18 , wherein the cathode comprises a material from a group of a composite of a polyaniline (PANI) conductive polymeric material and carbon black and a composite of poly (3,4-ethylenedioxythiophene) (PEDOT) and carbon nanotubes.

28 . The device of claim 18 , wherein when the voltage applied to the cathode and anode is removed, the salt dissolves in the phase change material, and the phase change material changes from the solid to the liquid at the first temperature when the salt is dissolved in the phase change material.

29 . The device of claim 18 , wherein the salt is dissolved in the phase change material when the device is in a first ambient temperature, wherein the salt is substantially removed from the phase change material when the device is in a second ambient temperature, and wherein the first ambient temperature is a lower temperature than the second ambient temperature.

30 . The device of claim 29 , wherein the first ambient temperature occurs at night time, and wherein the second ambient temperature occurs at day time.

31 . The device of claim 29 , wherein the first ambient temperature occurs in winter time, and wherein the second ambient temperature occurs in summer time.

32 . The device of claim 18 , wherein when the voltage is applied to the anode and the cathode, cations of the salt are incorporated into the anode and anions of the salt are incorporated into the cathode.

33 . The device of claim 18 , wherein the voltage applied to the anode and the cathode is about 2.5 volts (V) or less.

Assignments (2)
CONFIRMATORY LICENSE Recorded May 30, 2023
From: UNIVERSITY OF CALIF-LAWRENC BERKELEY LAB
To: UNITED STATES DEPARTMENT OF ENERGY
Reel/Frame 063797/0149 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 16, 2022
From: PRASHER, RAVI; KAUR, SUMANJEET; LIU, GAO; DAMES, CHRISTOPHER; LAU, JONATHAN; LILLEY, DREW; KHOMEIN, PIYACHAI; PAPP, JOSEPH
To: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
Reel/Frame 061117/0486 →
Continuity (2)
Provisional Application 63240497 · Sep 3, 2021
Related Publication 20230187686A1 · Jun 15, 2023
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