Honeycomb porous carbon electrode material, preparation method and application

Abstract

The invention provides a honeycomb porous carbon electrode material, a preparation method and application. According to the electrode material, a metal organic framework (MOF) material is used as a template and is subjected to ball milling and mixing with alkali metal citrate, and honeycomb-shaped porous carbon is obtained through high-temperature sintering; the metal organic framework material is selected from at least one of ZIF-8, MOF-5, ZIF-62 and MOF-74, the alkali metal citrate is selected from at least one of potassium citrate, sodium citrate and lithium citrate, and the mass ratio of the metal organic framework material to the alkali metal citrate is 1: (1-20). The preparation method comprises the steps of ball-milling mixing, high-temperature sintering, cleaning and drying. The method is simple in process and easy for large-scale production, and a new way is provided for preparation of high-performance energy storage device electrode materials.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and in particular to a method for preparing a honeycomb porous carbon electrode material, and application of the material prepared by the method in zinc-iodine battery positive electrode materials. Background Art

[0002] Porous carbon materials have broad application prospects in electrochemical energy storage due to their high specific surface area, excellent conductivity, and chemical stability. However, traditional porous carbon material preparation methods suffer from complex processes, uneven pore size distribution, and a monotonous pore structure, limiting their application in high-performance batteries. Furthermore, porous carbon materials prepared using existing methods often suffer from low specific capacity and poor cycling stability when used as battery electrode materials.

[0003] Metal-organic frameworks (MOFs) are considered ideal templates for preparing porous carbon materials due to their highly ordered pore structures and tunable chemical properties. Pyrolysis of MOFs can yield porous carbon materials with high surface area and uniform pore structure, but simple pyrolysis of MOFs is difficult to precisely control pore size and optimize pore structure. Alkali metal citrates, as a novel activator, can react with carbon precursors at high temperatures to generate porous structures, but their combination with MOF templates to prepare honeycomb-like porous carbon materials has not been reported.

[0004] Therefore, developing a method for preparing porous carbon materials with simple process, controllable structure and excellent performance is of great significance for promoting their application in the field of electrochemical energy storage. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing a honeycomb porous carbon electrode material. The method prepares a high-performance porous carbon material with a uniform honeycomb pore structure through the synergistic effect of a metal organic framework material (MOF) and an alkali metal citrate, and applies the material to the positive electrode material of a zinc-iodine battery.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a honeycomb porous carbon electrode material, which uses a metal organic framework material (MOF) as a template, is ball-milled and mixed with alkali metal citrate, and sintered at a high temperature to obtain a honeycomb porous carbon; the mass ratio of the metal organic framework material to the alkali metal citrate is 1:(1-20).

[0008] Furthermore, the metal organic framework material is at least one selected from ZIF-8, MOF-5, ZIF-62, MOF-74 or zinc-containing MOF materials.

[0009] Furthermore, the alkali metal citrate is selected from at least one of potassium citrate, sodium citrate and lithium citrate.

[0010] In a second aspect, the present invention provides a method for preparing the above-mentioned honeycomb porous carbon electrode material, the preparation method comprising the following steps:

[0011] (1) A certain amount of metal organic framework material and alkali metal citrate are placed in a ball mill and continuously ball milled.

[0012] (2) The product of step (1) is placed in a sintering furnace and kept warm in the sintering furnace for 2-8 hours under a continuous inert gas flow.

[0013] (3) Soak the product of step (2) in a large amount of deionized water, filter and wash it, and then dehydrate and dry it.

[0014] Furthermore, the ball milling time in step (1) is 1 to 10 hours.

[0015] Furthermore, the sintering temperature in step (1) is 600-1200°C.

[0016] The honeycomb porous carbon electrode material prepared in the present invention has the following characteristics:

[0017] a. The pore size distribution centers are located near 0.8nm, 1.2nm and 3.0nm;

[0018] b.BET specific surface area is 3000-3600m 2 / g;

[0019] c. The Raman spectrum ID / IG ratio is between 0.8-1.5.

[0020] In a third aspect, the present invention also provides an application of the above-mentioned honeycomb porous carbon material in the positive electrode material of a zinc-iodine battery, characterized in that: as a positive electrode carrier of a zinc-iodine battery; the iodine loading can reach 70%, and the capacity retention rate after 400 cycles is ≥90%, and the performance is greatly improved.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention prepares a porous carbon material with a uniform honeycomb pore structure through the synergistic effect of metal-organic framework materials and alkali metal citrate, with controllable pore size distribution and high specific surface area.

[0023] 2. When used as a positive electrode carrier for zinc-iodine batteries, this material has high iodine loading and excellent cycle stability, with a capacity retention rate of ≥90% after 400 cycles.

[0024] 3. The method of the present invention has simple process, readily available raw materials, and is easy to scale up for production, and has significant novelty, creativity, and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The X-ray diffraction patterns (XRD) of the honeycomb porous carbon materials prepared in Examples 1, 2, and 3.

[0026] Figure 2 These are scanning electron microscope images (SEM) of the honeycomb porous carbon materials prepared in Examples 1, 2, and 3.

[0027] Figure 3 1. The nitrogen adsorption-desorption curve and pore size distribution diagram of the honeycomb porous carbon material prepared in Example 1.

[0028] Figure 4 This is a charge and discharge cycle performance diagram of a zinc-iodine battery assembled with iodine-loaded honeycomb porous carbon material prepared in Example 1. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the following examples, but the protection scope of the present invention is not limited thereto.

[0030] Example 1

[0031] Weigh 1 g ZIF-8 and 5 g sodium citrate, place them in a ball mill with a ball-to-material ratio of 20:1, and mill for 5 h.

[0032] The ball-milled mixture was placed in a tube furnace and kept at 800 °C for 4 h under argon protection;

[0033] The sintered product was soaked in deionized water, filtered and washed, and then placed in an oven at 80° C. to dry for 12 hours to obtain a honeycomb porous carbon material.

[0034] The BET specific surface area of ​​the obtained material was 3200 m 2 / g, with pore size distribution centers located near 0.8nm, 1.2nm, and 3.0nm, and a Raman spectrum ID / IG ratio of 1.2. This material was used as a positive electrode carrier for zinc-iodine batteries, with an iodine loading of 70% and a capacity retention of 92% after 400 cycles.

[0035] Example 2

[0036] Weigh 0.5 g MOF-5 and 10 g potassium citrate, place them in a ball mill with a ball-to-material ratio of 20:1, and ball mill for 8 h.

[0037] The ball-milled mixture was placed in a tube furnace and kept at 1000 °C for 6 h under nitrogen protection;

[0038] The sintered product was soaked in deionized water, filtered and washed, and then placed in an oven at 80° C. to dry for 12 hours to obtain a honeycomb porous carbon material.

[0039] The BET specific surface area of ​​the obtained material was 3500m 2 / g, with pore size distribution centers located near 0.8nm, 1.2nm, and 3.0nm, and a Raman spectrum ID / IG ratio of 1.0. This material was used as a positive electrode carrier for zinc-iodine batteries, with an iodine loading of 68% and a capacity retention of 91% after 400 cycles.

[0040] Example 3

[0041] Weigh 2 g ZIF-62 and 20 g lithium citrate, place them in a ball mill with a ball-to-material ratio of 20:1, and ball mill for 10 h.

[0042] The ball-milled mixture was placed in a tube furnace and kept at 1200 °C for 2 h under argon protection;

[0043] The sintered product was soaked in deionized water, filtered and washed, and then placed in an oven at 80° C. to dry for 12 hours to obtain a honeycomb porous carbon material.

[0044] The BET specific surface area of ​​the obtained material was 3600m 2 / g, with pore size distribution centers located near 0.8nm, 1.2nm, and 3.0nm, and a Raman spectrum ID / IG ratio of 1.5. This material was used as a positive electrode carrier for zinc-iodine batteries, with an iodine loading of 70% and a capacity retention of 90% after 400 cycles.

[0045] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A honeycomb porous carbon electrode material, characterized in that: The electrode material uses a metal organic framework material (MOF) as a template, is ball-milled and mixed with alkali metal citrate, and sintered at high temperature to obtain honeycomb porous carbon; the mass ratio of the metal organic framework material to the alkali metal citrate is 1:(1-20).

2. The honeycomb porous carbon electrode material according to claim 1, characterized in that: The metal organic framework material is at least one selected from ZIF-8, MOF-5, ZIF-62, MOF-74 or zinc-containing MOF materials.

3. The honeycomb porous carbon electrode material according to claim 1, characterized in that: The alkali metal citrate is selected from at least one of potassium citrate, sodium citrate and lithium citrate.

4. A method for preparing a honeycomb porous carbon electrode material, characterized in that: The preparation method is used to prepare the honeycomb porous carbon electrode material according to any one of claims 1 to 3, and the preparation method comprises the following steps: (1) A certain amount of metal organic framework material and alkali metal citrate are placed in a ball mill and continuously ball milled. (2) The product of step (1) is placed in a sintering furnace and kept warm in the sintering furnace for 2-8 hours under a continuous inert gas flow. (3) Soak the product of step (2) in a large amount of deionized water, filter and wash it, and then dehydrate and dry it.

5. The method for preparing a honeycomb porous carbon electrode material according to claim 4, characterized in that: The metal organic framework material accounts for 4-50 wt.% of the mixed material in step (1).

6. The method for preparing a honeycomb porous carbon electrode material according to claim 1, wherein: The ball milling time in step (1) is 1 to 10 hours.

7. The method for preparing a honeycomb porous carbon material according to claim 1, wherein: The sintering temperature in step (1) is 600-1200°C.

8. The method for preparing a honeycomb porous carbon electrode material according to claim 1, wherein: The honeycomb porous carbon material finally obtained meets the following requirements: a) the pore size distribution centers are around 0.8nm, 1.2nm and 3.0nm; b) the BET specific surface area is between 3000-3600m 2 g -1 ; c) Raman spectrum ID / IG ratio is between 0.8-1.

5.

9. Use of a honeycomb porous carbon electrode material prepared according to any one of claims 1 to 3 or any one of claims 4 to 8 as a positive electrode material for zinc-iodine batteries, characterized in that: As a positive electrode carrier of zinc-iodine batteries, the iodine loading reaches 70%, and the capacity retention rate is ≥90% after 400 cycles.

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