A method for preparing a wood electrode having excellent ion diffusion efficiency

Abstract

The application provides a wood electrode material preparation method which utilizes wood natural channels to combine multi-scale ion channels for synergistic design, thereby significantly improving ion diffusion efficiency. The method retains the original directional microchannel structure of wood, and uniformly loads active materials (molybdenum disulfide, graphene oxide or nano titanium dioxide) with rich intra-layer mesoporous structures on the surface of wood cell walls. The natural multi-stage channels of wood provide a natural channel for efficient transmission of electrolyte ions; among them, the cell cavity can significantly shorten the ion migration path and improve the accessibility of ions to active sites. The channels formed by the stacking of nanosheets and the intra-layer mesopores further construct a transverse and longitudinal ion diffusion network. Through the synergistic effect of natural wood channels and nanomaterial channels, a continuous and efficient multi-scale ion transmission path is formed, which significantly improves the ion diffusion performance and energy storage capacity of the electrode material, and provides a new strategy for the development of green and high-performance energy storage devices.

Description

Technical Field

[0001] This invention relates to the fields of wood electrode material preparation and electrochemical energy storage technology, specifically to a method for preparing a wood electrode that improves ion diffusion efficiency through the synergistic effect of multi-scale ion channels, which has great potential in the field of new green energy. Background Technology

[0002] Natural wood, with its unique hierarchical porous structure (including cell cavities, pits, and cell wall nanopores), is considered an ideal template for constructing high-performance energy storage materials. However, the inherent insulating properties of wood severely limit its application in the electrochemical field. While traditional high-temperature carbonization significantly improves the conductivity of wood, the violent pyrolysis process destroys the fine structure of the cellulose skeleton, weakening its structural integrity and limiting its widespread application in energy storage devices. In recent years, wood electrode material preparation technology has achieved high conductivity and excellent electrochemical activity by introducing active nanosheet materials into the cell cavities of natural wood, while preserving the connectivity between the cell cavities and cellulose micropores, thus significantly enhancing its overall electrochemical performance. However, although filling the cell cavities of wood with active nanosheet materials can endow wood with excellent energy storage performance, the tendency of nanosheets to stack often leads to hindered ion diffusion, making it difficult to meet the energy storage requirements of high rate and high cycle stability. The effective transport of electrolyte ions depends not only on the intrinsic chemical properties of the active material but also on the multi-scale characteristics of the porous structure in the electrode. The rationality of pore size distribution, the connectivity of pores, and the tortuosity of the structure collectively determine the diffusion rate of ions within the electrode and the overall electrochemical performance. Therefore, by rationally designing a multi-level and interconnected pore network and optimizing the pore size structure, it is possible to maintain high energy storage capacity while improving the ion diffusion rate, which has important guiding significance for the design of high-performance supercapacitors and battery electrode materials. Summary of the Invention

[0003] This invention provides a method for preparing wood electrode materials that enhance ion diffusion efficiency through the synergistic effect of multi-scale ion channels. The method involves loading highly porous, active nanosheet materials (molybdenum disulfide, graphene oxide, and nano-titanium dioxide) onto the surface of wood cell walls. This combines the natural hierarchical pores of wood, the pores formed by stacked nanosheets, and the intralayer mesopores of the nanomaterials to synergistically construct multi-level ion transport channels spanning from the micrometer to the nanometer scale. Specifically, the directional pores formed by cell cavities in wood are straight, acting as "highways" to shorten the migration path of electrolyte ions within the electrode. Simultaneously, the micrometer-sized pores of the cell cavities provide a "reservoir" function, storing electrolytes and improving the accessibility of ions to active substances on the cell wall surface. The pore structure formed by stacked nanosheets further promotes the lateral diffusion of electrolyte ions within the stacked layers, while the intralayer mesopores of the active materials provide a rapid longitudinal diffusion path for ions. By leveraging the synergistic effect of natural wood pores, stacked nanosheet pores, and mesopores within the nanosheet layers, a highly efficient multi-level ion transport network is established, thereby significantly improving the ion diffusion efficiency of the wood electrode and providing a solid structural foundation for its application in high-performance energy storage devices.

[0004] The technical solution of the present invention specifically includes the following steps:

[0005] First, natural wood is pretreated (e.g., dried, cleaned) to remove surface impurities. Then, the pretreated wood is impregnated in a suspension of active nanosheets with abundant intralayer mesoporous structures. Next, the nanosheets are uniformly composited onto the cell wall surface at room temperature, forming a stable stacked structure. This stacked structure not only possesses abundant pores itself but also synergizes with the natural hierarchical pores of the wood, constructing a continuous, interconnected, and highly efficient ion transport network from the micrometer to the nanometer scale. This significantly improves the ion diffusion efficiency and overall electrochemical performance of the electrode material.

[0006] The method of this invention has the following advantages: 1. It preserves the natural multi-level porous structure of wood, giving full play to the intrinsic advantages of wood as an ion transport medium. 2. The porous structure of the nanomaterials themselves and the pores formed during their accumulation process work synergistically with the multi-level pores of wood to jointly construct a highly efficient ion transport channel, significantly improving the ion diffusion efficiency of the wood electrode. Detailed Implementation

[0007] Example 1

[0008] Balsa wood was cut into 2*2*0.5cm pieces and pretreated (e.g., washed and dried) to remove surface impurities. Then, molybdenum disulfide, rich in intralayer mesopores, was dispersed in water to form a stable mesoporous molybdenum disulfide suspension (5 mg / mL). Under vacuum-assisted conditions, this suspension was injected into the cell cavities of the wood, and the solvent was allowed to evaporate naturally at room temperature, allowing the nanosheets to uniformly composite onto the cell wall surface, thus obtaining a wood electrode with excellent ion diffusion efficiency. The pore size data, specific capacitance, and rate characteristics of the obtained wood electrode are shown in Table 1.

[0009] Example 2

[0010] Balsa wood was cut into 2*2*0.5cm pieces and pretreated (e.g., washed and dried) to remove surface impurities. Then, graphene oxide with abundant intralayer mesopores was dispersed in water to form a stable mesoporous graphene oxide suspension (5mg / mL). Under vacuum-assisted conditions, this suspension was injected into the cell cavities of wood, and the solvent was allowed to evaporate naturally at room temperature, allowing the nanosheets to uniformly composite onto the cell wall surface, thus obtaining a wood electrode with excellent ion diffusion efficiency. The pore size data, specific capacitance, and rate characteristics of the obtained wood electrode are shown in Table 1.

[0011] Example 3

[0012] Balsa wood was cut into 2*2*0.5cm pieces and pretreated (e.g., washed and dried) to remove surface impurities. Then, nano-titanium dioxide with abundant intralayer mesoporous structures was dispersed in water to form a stable mesoporous nano-titanium dioxide suspension (5mg / mL). Under vacuum-assisted conditions, this suspension was injected into the cell cavities of wood, and the solvent was allowed to evaporate naturally at room temperature, allowing the nanosheets to uniformly aggregate on the cell wall surface, thus obtaining a wood electrode with excellent ion diffusion efficiency. The pore size data, specific capacitance, and rate characteristics of the obtained wood electrode are shown in Table 1.

[0013] Table 1. Aperture data, specific capacitance, and rate capability of different embodiments and comparative examples.

[0014]

[0015] Note:

[0016] The specific capacitance and rate performance results were obtained by testing with a Gamry electrochemical workstation (Reference 600+); the specific surface area results were obtained by testing with a fully automated specific surface area and porosity analyzer (ASPA2020).

Claims

1. This invention relates to a method for preparing a wood electrode with excellent ion diffusion efficiency, characterized in that... Includes the following steps: First, the natural wood is pretreated (e.g., dried and cleaned) to remove surface impurities. Then, the pretreated wood is immersed in a suspension of active nanosheet materials (molybdenum disulfide, graphene oxide, and nano-titanium dioxide) with abundant intralayer mesopores. At room temperature, the nanosheets are uniformly composited on the cell wall surface to form a stable stacked structure. This stacked structure not only has abundant pores but also works synergistically with the natural multi-level pores of the wood to construct a continuous and interconnected high-efficiency ion transport network from the micrometer to the nanometer scale, thereby significantly improving the ion diffusion efficiency and overall electrochemical performance of the electrode material.

2. The method for preparing a wood electrode with excellent ion diffusion efficiency according to claim 1, characterized in that: The functional nanosheet materials include molybdenum disulfide, graphene oxide, and nano-titanium dioxide.

3. The method for preparing a wood electrode with excellent ion diffusion efficiency according to claim 1, characterized in that: The natural woods mentioned include balsa wood, linden wood, poplar wood, and all other types of wood.

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