# US 9,038,709 B2 · Thermal energy storage materials > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,038,709 B2 - Document ID: US9038709B2 - Status: Granted - Kind: B2 - Application number: 13/324,602 - Filed: 2011-12-13 - Published: 2012-08-30 - Granted: 2015-05-26 - Earliest claimed: 2008-02-22 - Assignees: Dow Global Technologies LLC - Applicants: David H. Bank; Andrey N. Soukhojak; Kalyan Sehanobish; David G. McLeod - Inventors: David H. Bank; Andrey N. Soukhojak; Kalyan Sehanobish; David G. McLeod - Web page: https://patentgrep.com/patent/US9038709B2 ## CPC - C09K 5/063: {Materials absorbing or liberating heat during crystallisation; Heat storage materials} - F28D 20/023: {the latent heat storage material being enclosed in granular particles or dispersed in a porous, fibrous or cellular structure} - F28F 23/00: Features relating to the use of intermediate heat-exchange materials, e.g. selection of compositions (heat-transfer, heat-exchange or heat-storage materials C09K5/00) - Y02B 10/20: Solar thermal - Y02E 60/14: Thermal energy storage - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general) - F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract The thermal energy storage material (TESM) system includes a container having a wall surface, and a TESM in at least partial contact with the wall surface. The TESM may include, consist essentially of, or consist of a metal containing compound comprising lithium, one or more different metal cations (i.e., different from lithium) and one or more polyatomic anions. The TESM may have a liquidus temperature, TL, from about 100° C. to about 250° C. The TESM may exhibits a heat storage density from 1 MJ/l to 1.84 MJ/l, as measured from 300° C. to 80° C. The TESM system may be free of water. If any water is present in the TESM system, the water concentration preferably is less than 10 wt. %. Preferably, the TESM system is generally resistant to corrosion at temperatures of about 300° C. ## Claims ### Claim 1 A thermal energy storage material system comprising: a. a container having a wall surface; and b. a thermal energy storage material in at least partial contact with the wall surface, wherein the thermal energy storage material is a metal containing compound comprising i) a lithium cation and at least one different metal cation different from lithium; and ii) one or more polyatomic anions, wherein the thermal energy storage material has a liquidus temperature, TL, from 100° C. to 250° C. ### Claim 2 (depends on 1) The thermal energy storage material system of claim 1, wherein the one or more polyatomic anions includes a nitrate anion or a nitrite anion; and the at least one additional metal cation includes a metal cation selected from the group consisting of group IA metals different from lithium, group IIA metals, and group IIIA metals. ### Claim 3 (depends on 2) The thermal energy storage material system of claim 2, wherein the thermal energy storage material is free of water or includes less than 10 wt. % of water. ### Claim 4 (depends on 1) The thermal energy storage material system of claim 1 wherein the at least one different metal cation includes Na, K, Be, Mg, Ca, Al, or Ga. ### Claim 5 (depends on 1) The thermal energy storage material system of claim 1, wherein the at least one different metal cation includes potassium cations, sodium cations, or both. ### Claim 6 (depends on 1) The thermal energy storage material system of claim 1, wherein the metal containing compound comprises a nitrite anion and at least one additional anion. ### Claim 7 (depends on 1) The thermal energy storage material system of claim 1, wherein the metal containing compound comprises a nitrate anion and at least one additional anion. ### Claim 8 (depends on 1) The thermal energy storage material system of claim 1, wherein the metal containing compound comprises: a) greater than 30 mole % lithium cations based on the total moles of to cations in the thermal energy storage material; and b) greater than 30 mole % nitrate anions based on the total moles of anions in the thermal energy storage material. ### Claim 9 (depends on 1) The thermal energy storage material system of claim 1, wherein the metal containing compound comprises: a) from about 40 to about 80 mole % nitrate anions based on the total moles of anions in the thermal energy storage material; and b) from about 20 to about 60 mole % nitrite anions based on the total moles of anions in the thermal energy storage material. ### Claim 10 (depends on 1) The thermal energy storage material system of claim 1, wherein the absolute value of the change in mass of the wall surface in contact with the thermal energy storage material is less than 1 g per m2 of the wall surface in contact with the thermal energy storage material after 45 days exposure to the thermal energy storage material at 300° C. in an inert atmosphere. ### Claim 11 (depends on 1) The thermal energy storage material system of claim 1, wherein the thermal energy storage material does not decompose at temperatures below 300° C. ### Claim 12 (depends on 1) The thermal energy storage material system of claim 1, wherein the thermal energy storage material does not have a solid to gas phase transition or a liquid to gas phase transition at a temperature below 300° C. ### Claim 13 (depends on 1) The thermal energy storage material system of claim 1, wherein the thermal energy storage material exhibits a heat storage density from 300° C. to 80° C. of at least 1 MJ/l. ### Claim 14 (depends on 1) The thermal energy storage material system of claim 1, wherein the thermal energy storage material is encapsulated in a plurality of capsules, including capsules having a volume of less than 200 ml. ### Claim 15 (depends on 14) The thermal energy storage material system of claim 14, wherein the wall surface of the container includes a metal oxide, and wherein the capsules include cavities and the thermal energy storage material fills 70% or more of the cavities. ### Claim 16 (depends on 1) The thermal energy storage material system of claim 1, wherein the thermal energy storage material includes lithium nitrate at a concentration from about 35 mole % to about 65 mole % based on the total moles of thermal energy storage material. ### Claim 17 (depends on 1) The thermal energy storage material system of claim 1, wherein the thermal energy storage material includes a nucleator. ### Claim 18 (depends on 1) The thermal energy storage material system of claim 1, wherein the total concentration of lithium nitrate and sodium nitrate is greater than 95 weight % based on the total weight of the metal containing compound. ### Claim 19 A thermal energy storage material system comprising: a. a container having a wall surface; and b. a thermal energy storage material in at least partial contact with the wall surface, wherein the thermal energy storage material is a metal containing compound comprising i) at least two different metal cations; and ii) a polyatomic anion, wherein the thermal energy storage material has a liquidus temperature, TL, from 100° C. to 250° C.; and the thermal energy storage material exhibits a heat storage density from 1 MJ/l to 1.83 MJ/l, wherein the heat storage density is measured from 300° C. to 80° C. ### Claim 20 (depends on 19) The thermal energy storage material system of claim 19, wherein the polyatomic anion is a nitrate anion or a nitrite anion; the at least two different metal cations includes at least two different metal cations selected from the group consisting of group IA metals, group IIA metals, and group IIIA metals; and the thermal energy storage material is free a water or includes less than 10 wt. % of water.