NiO / C composite material, preparation method thereof and application of NiO / C composite material in aqueous zinc-iodine battery
By preparing NiO/C composite materials as cathode materials for zinc-iodine batteries, the problems of polyiodide shuttle effect and iodine redox reaction lag in zinc-iodine batteries were solved, improving the electrochemical performance and stability of the batteries and achieving high capacity and long cycle life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LIAONING UNIVERSITY
- Filing Date
- 2026-01-28
- Publication Date
- 2026-05-05
AI Technical Summary
Existing zinc-iodine batteries suffer from the problem of intermediate polyiodides that are prone to shuttle effects during charging and discharging, leading to irreversible loss of active materials and self-discharge side reactions. Furthermore, the redox reaction kinetics of iodine are sluggish, resulting in low battery capacity, rapid decay of coulombic efficiency, and insufficient cycle stability, which hinders the commercialization process.
NiO/C composite material is used as the positive electrode material. It is prepared by hydrothermal method and calcination method. Iodine is anchored on NiO/C composite material by gas phase thermal diffusion method. It is then mixed with binder and conductive material to prepare a positive electrode sheet coated on substrate to form NiO/C anchored iodine composite material.
It significantly improved the conductivity and ion diffusion rate of the material, increased the specific surface area, improved the specific capacity and rate performance during charge and discharge, and enhanced the stability and capacity of the electrode, increasing it from 177 mAh/g to 215 mAh/g. The cycle life reached 1000 cycles with high capacity retention.
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Figure CN121983576A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrode material technology, specifically relating to a NiO / C composite material, its preparation method, and its application in aqueous zinc-iodine batteries. Background Technology
[0002] With the continuous growth of global energy demand and the environmental pressure brought about by the consumption of fossil fuels, the development of advanced energy storage systems that combine high economic efficiency, environmental friendliness, and long-term cycle stability has become an urgent task. Among various electrochemical energy storage technologies, lithium-ion batteries, with their excellent energy density and cycle life, have become the mainstream solution for grid connection and utilization of intermittent renewable energy sources such as solar and wind power. However, due to factors such as the low abundance and uneven distribution of lithium resources in the Earth's crust, lithium-ion batteries face technical bottlenecks such as high raw material costs and strong supply chain dependence. Facing the increasingly stringent requirements for energy storage devices from the electrification of rail transit and next-generation portable electronic devices, there is an urgent need to develop an alternative electrochemical energy storage technology that is abundant in resources, low in cost, and inherently safe.
[0003] Rechargeable aqueous zinc-ion batteries (RAZBs), with their inherently safe aqueous electrolyte system and the low cost, suitable redox potential, and high theoretical specific capacity of the zinc anode, are considered a highly competitive energy storage alternative in the post-lithium battery era. In the selection of cathode materials, halogen materials (chlorine, bromine, and iodine) based on conversion reaction mechanisms have attracted much attention due to their high theoretical specific capacity and wide availability. Iodine, in particular, is extremely abundant in the Earth's crust and oceans, providing a solid resource foundation for the large-scale application of zinc-iodine batteries. Zinc-iodine batteries are considered one of the most promising aqueous battery systems for industrialization due to their excellent balance between electrochemical performance and cost-effectiveness. However, existing zinc-iodine battery technology still faces serious challenges in practical applications: on the one hand, the intermediate polyiodides generated during charging and discharging are prone to shuttle effects, which not only lead to irreversible loss of active materials but also migrate to the anode surface, triggering self-discharge side reactions; on the other hand, the redox reaction of iodine involves a complex multi-step conversion process, and its reaction kinetics are relatively sluggish. The aforementioned problems collectively lead to low actual battery capacity, rapid decay of coulombic efficiency, and insufficient cycle stability, severely restricting the commercialization process of zinc-iodine batteries. Summary of the Invention
[0004] To address the above problems, this invention provides a NiO / C composite material, its preparation method, and its application in aqueous zinc-iodine batteries.
[0005] The technical solution adopted in this invention is: a NiO / C composite material, with a molar ratio of C : NiO = (100 - 25) : 1.
[0006] A method for preparing a NiO / C composite material includes: dissolving nickel salt and urea in a mixed solution of deionized water and ethylene glycol, adding biomass carbon, stirring evenly at room temperature, transferring the resulting mixture to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene, carrying out a hydrothermal reaction, cooling to room temperature, centrifuging and washing, vacuum drying, and calcining the resulting product under an argon atmosphere to obtain the NiO / C composite material.
[0007] Furthermore, the nickel salt is nickel nitrate.
[0008] Furthermore, the biomass carbon is biomass carbon produced by calcining coconut shells.
[0009] Furthermore, the hydrothermal reaction is carried out at a temperature of 150 ℃ - 170 ℃ and for a time of 12 h - 13 h.
[0010] Furthermore, the calcination is performed by heating to 300℃-400℃ at a heating rate of 4℃ / min-6℃ / min and holding at that temperature for 2h-3h.
[0011] The present invention relates to the application of the NiO / C composite material as a cathode material in aqueous zinc-iodine batteries.
[0012] Further, the method includes the following steps: anchoring the active material iodine onto the NiO / C composite material by gas-phase thermal diffusion of NiO / C composite material with elemental iodine; mixing the obtained product with binder and conductive material evenly; adding a small amount of NMP as a solvent; mixing evenly; directly coating onto a substrate; and vacuum drying to obtain a positive electrode sheet coated with NiO / C anchored iodine composite material.
[0013] Furthermore, by mass ratio, NiO / C composite material : iodine = 1 : (1 - 3).
[0014] Furthermore, the adhesive is PVDF.
[0015] Furthermore, the conductive material is Super-p.
[0016] The beneficial effects of this invention are:
[0017] 1. This invention prepares NiO / C composite materials through a simple hydrothermal and calcination method, which significantly improves the conductivity and ion diffusion rate of the materials while reducing the internal resistance.
[0018] 2. The NiO / C composite material prepared by this invention has a nanosheet-like structure on its surface that increases the specific surface area of the material, thereby improving the specific capacity and rate performance of the material during charge and discharge.
[0019] 3. The NiO / C composite material prepared by this invention has the characteristics of low cost, environmental friendliness and high safety.
[0020] 4. The NiO / C composite material prepared by this invention has advantages such as high energy density and power density.
[0021] 5. The aqueous zinc-iodine battery provided by this invention has a simple synthesis and assembly process, is easy to operate and control, and is suitable for continuous large-scale production.
[0022] 6. The modified NiO / C composite material prepared according to the present invention, as an electrode material, improves the stability of the electrode and increases the capacity from 177 mAh / g to 215 mAh / g. Attached Figure Description
[0023] Figure 1 This is the XRD pattern of the NiO / C composite material prepared in Example 1.
[0024] Figure 2 This is the SEM image of the NiO / C composite material prepared in Example 1.
[0025] Figure 3 This is a specific capacity diagram of the NiO / C composite material prepared in Example 1.
[0026] Figure 4 This is a cycle diagram of the NiO / C composite material prepared in Example 1. Detailed Implementation
[0027] The technical solution of the present invention will be further described below, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.
[0028] Example 1 NiO / C composite material
[0029] I. Preparation Method
[0030] Nickel nitrate hexahydrate (0.13 g, 0.45 mmol) and urea (0.30 g, 5.00 mmol) were dissolved in a mixture of 17.5 mL deionized water and 17.5 mL ethylene glycol. Biomass char (0.3 g, 25.00 mmol) made from coconut shells was added, and the mixture was stirred at room temperature for 1 h to ensure thorough mixing. After thorough mixing, the mixture was transferred to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and hydrothermally reacted at 160 °C for 12 h. After the reactor had completely cooled to room temperature, the product was removed, washed three times by centrifugation with deionized water and anhydrous ethanol, and vacuum dried. The product was then transferred to a tube furnace and heated to 350 °C at a heating rate of 5 °C / min under an argon atmosphere. It was calcined at this temperature for 2 h and then naturally cooled to room temperature to obtain a NiO / C composite material with a C to NiO molar ratio of 50:1.
[0031] II. Testing
[0032] Figure 1 This is the XRD pattern of the NiO / C prepared in this embodiment. Figure 1 As can be seen, the XRD pattern of the sample is basically consistent with the standard pattern of NiO, with a carbon peak at 22°. This indicates that NiO / C was successfully synthesized.
[0033] Figure 2 This is a SEM image of NiO / C. (Source: [Insert source here]) Figure 2 It is evident that the prepared NiO / C exhibits a typical plate-like structure.
[0034] Example 2 NiO / C composite material
[0035] Preparation method
[0036] Nickel nitrate hexahydrate (0.07 g, 0.23 mmol) and urea (0.30 g, 5.00 mmol) were dissolved in a mixture of 17.5 mL deionized water and 17.5 mL ethylene glycol. Biomass char (0.3 g, 25.00 mmol) made from coconut shells was added, and the mixture was stirred at room temperature for 1 h to ensure thorough mixing. After thorough mixing, the mixture was transferred to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and hydrothermally reacted at 160 °C for 12 h. After the reactor had completely cooled to room temperature, the product was removed, washed three times by centrifugation with deionized water and anhydrous ethanol, and vacuum dried. The product was then transferred to a tube furnace and heated to 350 °C at a heating rate of 5 °C / min under an argon atmosphere. It was calcined at this temperature for 2 h and then naturally cooled to room temperature to obtain a NiO / C composite material with a C to NiO molar ratio of 100:1.
[0037] Example 3 NiO / C composite material
[0038] Preparation method
[0039] Nickel nitrate hexahydrate (0.26 g, 0.9 mmol) and urea (0.30 g, 5.00 mol) were dissolved in a mixed solution of 17.5 mL deionized water and 17.5 mL ethylene glycol. Biomass char (0.3 g, 25.00 mmol) made from coconut shells was added, and the mixture was stirred at room temperature for 1 h to ensure thorough mixing. After thorough mixing, the mixture was transferred to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and hydrothermally reacted at 160 °C for 12 h. After the reactor had completely cooled to room temperature, the product was removed, washed three times by centrifugation with deionized water and anhydrous ethanol, and vacuum dried. The product was then transferred to a tube furnace and heated to 350 °C at a heating rate of 5 °C / min under an argon atmosphere. The mixture was calcined at this temperature for 2 h and then naturally cooled to room temperature to obtain a NiO / C composite material with a C to NiO molar ratio of 25:1.
[0040] Example 4: Application of NiO / C composite material as cathode material in aqueous zinc-iodine batteries
[0041] I. Aqueous Zinc-Iodine Batteries
[0042] 1. The preparation method is as follows:
[0043] 1) Preparation of positive electrode:
[0044] The NiO / C composite material prepared in Example 1 was mixed with elemental iodine at a mass ratio of 1:2, and the active substance iodine was anchored onto the NiO / C composite material by gas-phase thermal diffusion to obtain the NiO / C anchored iodine composite material.
[0045] Weigh 80 mg of NiO / C anchored iodine composite material, mix it with 10 mg of PVDF and 10 mg of Super-p, add a small amount of NMP as a solvent, mix it evenly, and then directly coat it onto the substrate carbon paper. Dry it in a vacuum drying oven at 60 ℃, and then take it out to obtain a positive electrode sheet coated with NiO / C anchored iodine composite material.
[0046] 2) Negative electrode preparation:
[0047] Zinc sheets with a thickness of 0.1 mm and a purity of 99.99% are repeatedly sanded to remove the oxide layer on the surface. The sanded zinc sheets are then cut into circles with a diameter of 12 mm to make negative electrode sheets.
[0048] 3) Assembling aqueous zinc-iodine batteries:
[0049] Using the positive electrode sheet prepared in step 1) as the positive electrode and the negative electrode sheet prepared in step 2) as the negative electrode, and selecting 1M zinc sulfate and 0.1M potassium iodide as the electrolyte, a NiO / C aqueous zinc-iodine battery is obtained.
[0050] 2. Electrochemical performance testing
[0051] Comparative Experiments: 1) Pure biomass carbon from coconut shells was mixed with elemental iodine at a mass ratio of 1:2 using a gas-phase thermal diffusion method to anchor the active material iodine onto the biomass carbon. 80 mg of the resulting product was weighed and mixed evenly with 10 mg of PVDF and 10 mg of Super-p. A small amount of NMP was added as a solvent, and the mixture was thoroughly mixed. This mixture was then directly coated onto a substrate carbon paper and dried in a vacuum drying oven at 60 ℃. The resulting positive electrode sheet coated with biomass carbon-anchored iodine was obtained. 2) A zinc sheet with a thickness of 0.1 mm and a purity of 99.99% was repeatedly sanded to remove the oxide layer. The sanded zinc sheet was then cut into circles with a diameter of 12 mm to form a negative electrode sheet. 3) Using the prepared positive electrode sheet as the positive electrode and the prepared negative electrode sheet as the negative electrode, a 1M zinc sulfate and 0.1M potassium iodide electrolyte was selected to obtain an AC aqueous zinc-iodine battery.
[0052] Figure 3 This is a specific capacity diagram of a NiO / C aqueous zinc-iodine battery. (From...) Figure 3 It is evident that the specific capacity of the NiO / C aqueous zinc-iodine battery is superior to that of the pure biomass carbon AC aqueous zinc-iodine battery made from coconut shells. The specific capacitance increased from 177 mAh / g to 215 mAh / g.
[0053] Figure 4 This is a cycle diagram of a NiO / C aqueous zinc-iodine battery. (From...) Figure 4 It can be seen that the NiO / C aqueous zinc-iodine battery, at a current density of 1 A·g -1 The material exhibits a high cycle life of 1000 cycles with excellent capacity retention. This is attributed to the more uniform and ordered deposition of NiO on the carbon in the NiO / C composite material formed at a molar ratio of C:NiO = 50:1. This increases the specific surface area of the material, providing more active sites and thus facilitating the storage of more iodide ions. Furthermore, it enhances the separation of elemental iodine and iodide ions, thereby improving its electrochemical performance. Figure 4 It is evident that the cycle stability of NiO / C aqueous zinc-iodine batteries is superior to that of AC aqueous zinc-iodine batteries made from pure biomass carbon calcined from coconut shells.
[0054] II. The Influence of NiO / C Composite Materials with Different Molar Ratios as Cathode Materials on the Electrochemical Performance of Assembled Aqueous Zinc-Iodine Batteries
[0055] 1. The preparation method is as follows:
[0056] 1) Preparation of positive electrode:
[0057] The NiO / C composite materials prepared in Examples 1-3 were respectively mixed with elemental iodine at a mass ratio of 1:2 and the active substance iodine was anchored onto the NiO / C composite material by gas-phase thermal diffusion method to obtain NiO / C anchored iodine composite materials.
[0058] 80 mg of NiO / C anchored iodine composite material was weighed and mixed with 10 mg of PVDF and 10 mg of Super-p. A small amount of NMP was added as a solvent and mixed evenly. The mixture was then directly coated onto a carbon paper substrate and dried in a vacuum drying oven at 60 °C. The resulting positive electrode sheets were coated with NiO / C anchored iodine composite materials with different C to NiO molar ratios.
[0059] 2) Negative electrode preparation:
[0060] Zinc sheets with a thickness of 0.1 mm and a purity of 99.99% are repeatedly sanded to remove the oxide layer on the surface. The sanded zinc sheets are then cut into circles with a diameter of 12 mm to make negative electrode sheets.
[0061] 3) Assembling aqueous zinc-iodine batteries:
[0062] Using the positive electrode sheet prepared in step 1) as the positive electrode and the negative electrode sheet prepared in step 2) as the negative electrode, and selecting 1M zinc sulfate and 0.1M potassium iodide as the electrolyte, different NiO / C aqueous zinc-iodine batteries were obtained.
[0063] 2. Electrochemical performance testing
[0064] Table 1. Effect of different molar ratios of NiO / C composite materials as cathode materials on the specific capacity of assembled aqueous zinc-iodine batteries.
[0065]
[0066] Based on the three different aqueous zinc-iodine batteries assembled according to the above embodiments, as shown in Table 1, Example 1 exhibits the best electrochemical performance. This is because, at a molar ratio of C:NiO = 50:1, the NiO in the formed NiO / C composite material is deposited more uniformly and orderly on the carbon, increasing the specific surface area of the material and providing more active sites. Therefore, it is easier to store more iodine ions, and it also has a more favorable effect on the separation of elemental iodine and iodine ions, thereby improving its electrochemical performance.
Claims
1. A NiO / C composite material, characterized in that, In the NiO / C composite material, the molar ratio is C : NiO = (100 - 25) :
1.
2. The method for preparing a NiO / C composite material according to claim 1, characterized in that, The preparation method includes: dissolving nickel salt and urea in a mixed solution of deionized water and ethylene glycol, adding biomass carbon, stirring evenly at room temperature, transferring the resulting mixture to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene, carrying out a hydrothermal reaction, cooling to room temperature, centrifuging and washing, vacuum drying, and calcining the resulting product under an argon atmosphere to obtain a NiO / C composite material.
3. The method for preparing a NiO / C composite material according to claim 2, characterized in that, The nickel salt is nickel nitrate.
4. The method for preparing a NiO / C composite material according to claim 2, characterized in that, The biomass carbon is biomass carbon produced by calcining coconut shells.
5. The method for preparing a NiO / C composite material according to claim 2, characterized in that, The hydrothermal reaction is carried out at a temperature of 150 ℃ - 170 ℃ for a time of 12 h - 13 h.
6. The method for preparing a NiO / C composite material according to claim 2, characterized in that, The calcination is performed by heating to 300℃-400℃ at a heating rate of 4℃ / min-6℃ / min and holding at that temperature for 2-3 hours.
7. The application of the NiO / C composite material as a cathode material in an aqueous zinc-iodine battery according to claim 1.
8. The application according to claim 7, characterized in that, The method includes the following steps: NiO / C composite material and elemental iodine are used to anchor the active material iodine onto the NiO / C composite material through gas-phase thermal diffusion. The resulting product is mixed evenly with a binder and conductive material. A small amount of NMP is added as a solvent and mixed evenly. The mixture is then directly coated onto a substrate and vacuum dried to obtain a positive electrode sheet coated with NiO / C anchored iodine composite material.
9. The application according to claim 8, characterized in that, By mass ratio, NiO / C composite material : iodine = 1 : (1 - 3).
10. The application according to claim 8, characterized in that, The adhesive is PVDF, and the conductive material is Super-p.