Hard Carbon Anode Structure for Higher Sodium-Ion Capacity
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Solution Overview
Problem
Current hard carbon (HC) anode materials for sodium-ion batteries exhibit low reversible specific capacity and poor initial efficiency, limiting their application due to small market share and inadequate interlayer spacing for sodium ion deintercalation.
Innovation Solution
A preparation method involving the mixing of zirconium or germanium compounds with amino-containing solutions, followed by lyophilization and calcination, to create a porous, multi-walled HC anode material with enhanced interlayer spacing, utilizing an inverted tree structure for in-situ polymerization and acid treatment to achieve a high surface area and improved structural porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional graphite anode material is used, then the structure is stable and easy to manufacture, but the interlayer spacing is too small for sodium ion deintercalation
Solution Approach 1:
The patent changes the interlayer spacing parameter from the traditional graphite structure (too small for Na ions) to a hard carbon structure with expanded interlayer spacing (0.38-0.42 nm). This is achieved through the sol-gel process using zirconium or germanium compounds as templates, which create a porous structure with larger spacing that accommodates sodium ions while maintaining structural stability.
Solution Approach 2:
The patent creates a composite hard carbon material incorporating metal oxide nanoparticles (ZrO2 or GeO2) within the carbon matrix. This composite structure provides both the expanded interlayer spacing needed for sodium ion insertion/extraction and the structural stability for cycling performance. The metal oxide particles act as spacers and structural support during the carbonization process.
2Reliability
If hard carbon anode material with large interplanar spacing is used, then sodium ion deintercalation is improved, but the reversible specific capacity and initial efficiency are low
Solution Approach 1:
The patent employs a porous hard carbon structure created through the sol-gel process followed by carbonization. The porous structure with controlled pore size distribution provides numerous pathways for sodium ion transport and insertion/extraction, enhancing both the deintercalation efficiency and the reversible specific capacity. The porosity allows for higher sodium ion accessibility without compromising structural integrity.
Solution Approach 2:
The patent introduces local quality variations through the distribution of metal oxide nanoparticles within the carbon matrix. These nanoparticles create localized regions with different electronic and structural properties that facilitate sodium ion insertion. The non-uniform distribution of pores and metal oxide particles creates diverse local environments that enhance overall capacity while maintaining good initial efficiency.
3Length of moving object
If hard carbon anode material is used, then the interlayer spacing is large for sodium ion accommodation, but the initial efficiency and cycling stability are poor
Solution Approach 1:
The patent creates a composite structure where metal oxide nanoparticles (ZrO2 or GeO2) are embedded within the hard carbon matrix. These metal oxide components provide structural support and maintain the expanded interlayer spacing during cycling, preventing structural collapse. The composite structure enhances cycling stability by providing mechanical strength while maintaining the porous architecture necessary for sodium ion transport over extended cycles.
Solution Approach 2:
The patent uses the metal oxide nanoparticles as structural cushions that prevent excessive volume changes and structural degradation during sodium ion insertion and extraction cycles. These nanoparticles act as sacrificial elements that absorb mechanical stress, protecting the carbon matrix from degradation and maintaining interlayer spacing stability throughout the cycling process, thereby improving long-term cycling performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in a HC anode material with increased cycling stability and energy density, as well as improved sodium ion and electron transport, enhancing the material's performance and capacity.
Implementation Method 1
utilizing an inverted tree structure for in-situ polymerization
Implementation Method 2
lyophilizing the post-reaction slurry to obtain a dry powder
Implementation Method 3
subjecting the dry powder to calcination in a protective atmosphere to obtain a calcined material
Implementation Method 4
soaking the calcined material in an acid liquid to obtain the HC anode material
Data Source
AI summary
The present disclosure discloses a preparation method of a hard carbon (HC) anode material and use thereof. The preparation method includes the following steps: mixing a substance A, a first alcohol liquid, and an oxidant to obtain a peroxide gel of the substance A, and dissolving a substance B in a second alcohol liquid to obtain an amino-containing solution; mixing the peroxide gel of the substance A with the amino-containing solution to allow a reaction to obtain a post-reaction slurry; and lyophilizing the post-reaction slurry to obtain a dry powder, subjecting the dry powder to calcination in a protective atmosphere to obtain a calcined material, soaking the calcined material in an acid liquid, and water-washing and drying to obtain the HC anode material.