Core-Shell Hard Carbon Anode Coating for Sodium-Ion Efficiency
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Solution Overview
Problem
Hard carbon materials used in sodium ion batteries suffer from poor conductivity, low initial efficiency, and low capacity, while graphite materials produce fine powder that reduces efficiency and capacity when used in sodium ion batteries, leading to waste and high manufacturing costs.
Innovation Solution
A core-shell structured negative electrode material is developed, comprising a hard carbon core coated with multiple layers of carbonized materials, including a carbon powder layer and a sodium supplementing agent, to enhance conductivity and efficiency, with specific particle sizes and surface areas optimized for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hard carbon material is used as negative electrode active material, then chemical stability is improved, but conductivity is worsened
Solution Approach 1:
The patent applies composite materials by coating hard carbon particles with carbon powder and carbonized polymer layers to create a composite structure that combines the chemical stability of hard carbon with the high conductivity of carbon powder, thereby resolving the contradiction between chemical stability and conductivity
Solution Approach 2:
The patent applies local quality by maintaining the hard carbon core structure for chemical stability while adding conductive carbon powder and carbonized polymer coatings on the surface to improve conductivity locally, achieving both chemical stability and improved conductivity through differentiated material properties in different regions
2Reliability
If hard carbon material is used as negative electrode active material, then chemical stability is improved, but initial Coulombic efficiency is worsened
Solution Approach 1:
The patent applies parameter changes by controlling the particle size of hard carbon within 3-15 μm and adjusting the coating thickness and composition to optimize the balance between chemical stability and initial Coulombic efficiency, achieving near-100% efficiency through optimized physical and chemical parameters
3Reliability
If hard carbon material is used as negative electrode active material, then chemical stability is improved, but capacity is worsened
Solution Approach 1:
The patent applies composite materials by combining hard carbon with carbon powder and carbonized polymer coatings to create a composite structure that enhances the capacity of hard carbon while maintaining its chemical stability, achieving higher overall capacity through material composition optimization
4Object-generated harmful factors
If graphite fine powder is used in lithium ion batteries, then conductivity is improved, but initial efficiency and capacity are worsened due to large specific surface area
Solution Approach 1:
The patent applies the blessing in disguise principle by taking graphite fine powder waste material with large specific surface area, which would normally reduce initial efficiency, and using it as a coating layer on hard carbon particles to improve conductivity while the controlled coating process ensures near-100% initial Coulombic efficiency in sodium ion batteries
5Object-generated harmful factors
If graphite is crushed to produce fine powder, then conductivity is improved, but manufacturing cost is worsened due to waste material
Solution Approach 1:
The patent applies the discarding and recovering principle by recovering and reusing graphite fine powder waste material from the crushing process as a valuable coating component, converting what would be discarded waste into a functional layer that improves conductivity and reduces manufacturing costs
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 multilayer-coated hard carbon material significantly improves initial Coulombic efficiency and cycle life, reduces manufacturing costs, and effectively utilizes carbon powder waste, achieving near-100% initial efficiency and higher capacity in sodium ion batteries.
Implementation Method 1
the negative electrode material can effectively improve the conductivity of a hard carbon material
Implementation Method 2
a first carbonized layer, a carbon powder layer and a second carbonized layer which are sequentially coated at the outer side of the core layer
Data Source
AI summary
Disclosed is a negative electrode material and a preparation method therefor. The negative electrode material is a core-shell structure, and comprises a core layer formed by hard carbon, and a first carbonized layer, a carbon powder layer and a second carbonized layer which are sequentially coated at the outer side of the core layer. Further disclosed are a negative electrode plate prepared by the negative electrode material, and a sodium ion battery. The negative electrode material of the present disclosure can effectively improve the conductivity of a hard carbon material, thereby facilitating improvement of the performance such as initial Coulombic efficiency and cycle life of the sodium ion battery.