Search

US-12617996-B2 - Highly thermally conductive heat storage material, preparation method therefor, and application thereof, and composition for preparing highly thermally conductive heat storage material and application thereof

US12617996B2US 12617996 B2US12617996 B2US 12617996B2US-12617996-B2

Abstract

The present invention relates to the fields of heat storage and thermally conductive materials, and discloses a highly thermally conductive heat storage material, a preparation method therefor, and the application thereof, and a composition for preparing a highly thermally conductive heat storage material and the application thereof. The highly thermally conductive heat storage material comprises 11-41 wt % of a carbonaceous part and 59-89 wt % of a graphitic part; for the carbonaceous part, L c >18 nm, L a >35 nm, d 002 <0.3388 nm, and the degree of graphitization is 60% to 95%; for the graphitic part, L c >50 nm; L a >80 nm; d 002 <0.3358 nm, and the degree of graphitization is 95% to 100%. The highly thermally conductive heat storage material comprises a carbonaceous part with a specific structure and a graphitic part with a specific structure, and the heat storage material obtained thereby possesses high thermal conductivity and high compressive strength. Meanwhile, the preparation process of the highly thermally conductive heat storage material is simple and cost-effective.

Inventors

  • Dongfang ZHENG
  • Wenbin Liang
  • Chang Wei
  • Junqing Liu
  • Ying Sheng
  • Chunting DUAN
  • Jianming Wei
  • Guanghui GAO
  • Chengyu Wen

Assignees

  • China Energy Investment Corporation Limited
  • NATIONAL INSTITUTE OF CLEAN-AND-LOW-CARBON ENERGY

Dates

Publication Date
20260505
Application Date
20211126
Priority Date
20210331

Claims (17)

  1. 1 . A highly thermally conductive heat storage material, characterized in that, the highly thermally conductive heat storage material comprises a carbonaceous part and a graphitic part; wherein, based on the total weight of the highly thermally conductive heat storage material, the carbonaceous part is present in an amount of 11 wt % to 41 wt %, and the graphitic part is present in an amount of 59 wt % to 89 wt %; wherein the carbonaceous part has a microcrystal size Lc in a c-axis direction obtained by XRD of greater than 18 nm, a microcrystal size La in an a-axis direction of greater than 35 nm, an interlayer spacing d 002 of the crystal plane ( 002 ) of less than is 0.3388 nm, and a degree of graphitization of 60% to 95%; wherein the graphitic part has a microcrystal size Lc in a c-axis direction obtained by XRD of greater than 50 nm, a microcrystal size La in an a-axis direction of greater than 80 nm, an interlayer spacing d 002 of the crystal plane ( 002 ) of less than 0.3358 nm, and a degree of graphitization of 95% to 100%.
  2. 2 . The highly thermally conductive heat storage material according to claim 1 , wherein, the highly thermally conductive heat storage material has a bulk density of 1.9 g/cm 3 to 2.18 g/cm 3 is 1.9 g/cm 3 , a thermal conductivity of 500 W/mk to 800W/mk, a compressive strength of 29 MPa to 48 MPa, a ratio of the thermal conductivity to the compressive strength is 12 W/(m·k·MPa) to 25 W/(m·k·MPa).
  3. 3 . A composition for preparing a highly thermally conductive heat storage material, characterized in that, the composition comprises a graphite and a mesophase pitch; based on the total weight of the highly thermally conductive heat storage material composition, the graphite is present in an amount of 50 wt % to 85 wt %, and the mesophase pitch is present in an amount of 15 wt % to 50 wt %; wherein the mesophase pitch has a microcrystal size Lc in a c-axis direction, a microcrystal size La in an a-axis direction and an interlayer spacing d 002 of the crystal plane ( 002 ) obtained by XRD meet the following conditions: Lc>2 nm, La>12 nm, d 002 <0.3580 nm; wherein the mesophase pitch has a mesophase content of 30 wt % to 100 wt %, and a softening point of 300° C. to 400° C.; wherein the graphite has a microcrystal size Lc in a c-axis direction, a microcrystal size La in an a-axis direction and an interlayer spacing d 002 of the crystal plane ( 002 ) obtained by XRD meet the following conditions: Lc>50 nm, La>80 nm, d 002 <0.3358 nm.
  4. 4 . The composition according to claim 3 , wherein, the graphite is at least one selected from the group consisting of natural flake graphite, artificial graphite and spherical graphite.
  5. 5 . The composition according to claim 3 , wherein, the graphite has a carbon content of greater than 95 wt %.
  6. 6 . The composition according to claim 3 , wherein, based on the total weight of the highly thermally conductive heat storage material composition, the graphite is present in an amount of 60 wt % to 75 wt %, and the mesophase pitch is present in an amount of 25 wt % to 40 wt %.
  7. 7 . The composition according to claim 5 , wherein, the graphite has a carbon content of greater than 98 wt %.
  8. 8 . The composition according to claim 4 , wherein, the graphite has a carbon content of greater than is 95 wt %.
  9. 9 . A preparation method of a highly thermally conductive heat storage material, wherein, the preparation method comprises the following steps: (1) uniformly mixing components of the highly thermally conductive heat storage material composition to obtain a premix; (2) pressing the premix for pre-molding to obtain a pre-molded block; (3) subjecting the pre-molded block to hot press molding to obtain a molded sample; (4) subjecting the molded sample to heat treatment in an inert atmosphere to obtain the highly thermally conductive heat storage material; wherein, the composition comprises a graphite and a mesophase pitch; based on the total weight of the highly thermally conductive heat storage material composition, the graphite is present in an amount of 50 wt % to 85 wt %, and the mesophase pitch is present in an amount of 15 wt % to 50 wt %; wherein the mesophase pitch has a microcrystal size L c in a c-axis direction, a microcrystal size L a in an a-axis direction and an interlayer spacing d 002 of the crystal plane ( 002 ) of obtained by XRD that meet the following conditions: L c >2 nm, L a >12 nm, d 002 <0.3580 nm; wherein the mesophase pitch has a mesophase content of 30wt % to 100 wt %, and a softening point of 300° C. to 400° C.; wherein the graphite has a microcrystal size L c in a c-axis direction, a microcrystal size L a in an a-axis direction and an interlayer spacing d 002 of the crystal plane ( 002 ) obtained by XRD that meet the following conditions: L c >50 nm, L a >80 nm, d 002 <0.3358 nm.
  10. 10 . The preparation method according to claim 9 , wherein, the graphite is at least one selected from the group consisting of natural flake graphite, artificial graphite and spherical graphite.
  11. 11 . The preparation method according to claim 9 , wherein, the graphite has a carbon content of greater than 95 wt %.
  12. 12 . The preparation method according to claim 9 , wherein, based on the total weight of the highly thermally conductive heat storage material composition, the graphite is present in an amount of 60 wt % to 75 wt %, and the mesophase pitch is present in an amount of 25 wt % to 40 wt %.
  13. 13 . The preparation method according to claim 11 , wherein, in step (2), the premix is pressed at a molding pressure of 10 MPa to 40 MPa.
  14. 14 . The preparation method according to claim 11 , wherein, in step (3), the hot press molding is conducted at a molding temperature of 400° C. to 600° C., and a molding pressure of 10 MPa to 100 MPa.
  15. 15 . The preparation method according to claim 11 , wherein, in step (4), the heat treatment is conducted at a heat treatment temperature of 1600° C. to 3000° C.; and a heat treatment time of 0.5 hour to 10 hours.
  16. 16 . The preparation method according to claim 11 , wherein, the graphite has a carbon content of greater than is 98 wt %.
  17. 17 . The preparation method according to claim 15 , wherein, in step (4), the heat treatment is conducted at a heat treatment temperature of 2400° C. to 3000° C.; and a heat treatment time of 0.5 hour to 2 hours.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is the U.S. National Stage Application under 35 U.S.C. § 371 of International Patent Application No. PCT/CN2021/133550, filed on Nov. 26, 2021, which claims the benefit of Chinese patent application 202110351896.8, filed on Mar. 31, 2021, the entire disclosures of which are incorporated herein by reference. TECHNICAL FIELD The present invention relates to the fields of heat storage and thermally conductive materials, in particular to a highly thermally conductive heat storage material, preparation method therefor, and application thereof, and a composition for preparing highly thermally conductive heat storage material and application thereof. BACKGROUND Heat storage devices play an important role in solar thermal power, electric peak management, clean energy heating, waste heat utilization, etc. In the background of energy shortage, it is particularly important to be able to quickly and effectively utilize the heat from waste heat, valley electricity and clean energy. The high thermal conductivity of heat storage materials is conducive to achieving the goal of fast heat storage and release speed and high temperature uniformity, and the high temperature resistance of the material can achieve the goals of high heat storage temperature and high heat storage density. CN110550955A discloses an ultra-high thermal conductivity and high strength graphite block material and a preparation method thereof. The graphite block material is obtained by using a high-purity natural graphite powder as the heat transfer enhancer, a high-quality mesophase pitch as the binder, and a silicon-titanium-molybdenum ternary component as the catalytic graphitization additive, and using hot-pressing sintering at high temperature. The graphite block material, with a thermal conductivity of greater than 600 W/mK and a bending strength of greater than 50 MPa, is expected to play a significant role in the fields of high heat flux and diverse operating conditions such as thermal protection for aerospace vehicles, first wall of nuclear fusion, and high-power density electronic devices. Preparation of carbon/ceramic composite material with high thermal conductivity and the performance study thereof, published by Zhanjun Liu, etc., in the supplement of 2007 of Material Engineering, discloses that series of carbon/ceramic composite materials were prepared by using the natural flake graphite powder as the skeletal material carbon, the mesophase pitch as the binder and Si and Ti as additives, and using a hot press process. When the hot press temperature is 2700° C., the thermal conductivity of the material in the direction parallel to the graphite layer is 654 W/m·K, the thermal diffusion coefficient is 413 mm2/s, the bending strength is 34.5 MPa and the compressive strength is 31.5 MPa. In the above-mentioned composite materials, the Japanese naphthalene series AR mesophase pitch is used as the binder, which results in a high cost, and one-step hot press molding is adopted, which demands a high molding temperature, high process requirements, and a high energy consumption. SUMMARY The purpose of the present invention is to overcome the problems of high process requirements and high cost in the prior art, and provide a highly thermally conductive heat storage material, a preparation method therefor, and the application thereof, and a composition for preparing a highly thermally conductive heat storage material and the application thereof. The highly thermally conductive heat storage material comprises a carbonaceous part with a specific structure and a graphitic part with a specific structure, and thus a heat storage material with high thermal conductivity and compressive strength is obtained. Meanwhile, the preparation process of the highly thermally conductive heat storage material is simple and cost-effective. In order to achieve the above purposes, the first aspect of the present invention provides a highly thermally conductive heat storage material, characterized in that, the highly thermally conductive heat storage material comprises a carbonaceous part and a graphitic part; wherein, based on the total weight of the highly thermally conductive heat storage material, the content of the carbonaceous part is 11 wt % to 41 wt %, and the content of the graphitic part is 59 wt % to 89 wt %;the microcrystal size Lc in the c-axis direction of the carbonaceous part obtained by XRD is >18 nm; the microcrystal size La in the a-axis direction is >35 nm; the interlayer spacing d002 of the crystal plane (002) is <0.3388 nm; and the degree of graphitization is 60% to 95%;the microcrystal size Lc in the c-axis direction of the graphitic part obtained by XRD is >50 nm; the microcrystal size La in the a-axis direction is >80 nm; the interlayer spacing d002 of the crystal plane (002) is <0.3358 nm; and the degree of graphitization is 95% to 100%. The second aspect of the present invention provides