Hard Carbon Composite Negative Electrode for Sodium Batteries
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Solution Overview
Problem
Current carbon-based negative electrode active materials for sodium secondary batteries have limited sodium intercalation capacity and unsatisfactory initial efficiency and life characteristics.
Innovation Solution
A negative electrode active material comprising a hard carbon with a specific surface area of 50 m2/g or less and a D-band to G-band peak intensity ratio of 1 or less, combined with elements from Group 1, Group 2, or Groups 13 to 12, enhances reversible capacity and reduces initial irreversible capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon-based materials are used as negative electrode active material, then the battery structure is simple and manufacturing is easy, but the sodium intercalation capacity is small and initial efficiency is unsatisfactory
Solution Approach 1:
The patent uses a composite material consisting of hard carbon particles combined with metal particles (such as sodium, aluminum, or their alloys). This composite structure integrates the advantages of both materials: hard carbon provides a stable layered structure for sodium intercalation, while metal particles contribute to higher capacity and improved initial efficiency. The composite approach resolves the contradiction by maintaining manufacturing simplicity while significantly enhancing electrochemical performance.
Solution Approach 2:
The patent specifies controlling the specific surface area of hard carbon to be 50 m²/g or less and the D-band to G-band peak intensity ratio to be 1 or less in Raman spectroscopy. These parameter controls optimize the carbon structure to reduce irreversible capacity loss and improve initial efficiency, while still maintaining ease of manufacture through standard hard carbon production methods.
2Ease of manufacture
If carbon-based materials are used as negative electrode active material, then the manufacturing process is simple, but the sodium intercalation capacity is small
Solution Approach 1:
By combining hard carbon with metal particles (sodium, aluminum, or their alloys), the patent creates a composite that achieves high sodium intercalation capacity. The metal particles provide additional sodium storage sites and enhance the overall capacity beyond what hard carbon alone can achieve, while the hard carbon matrix maintains structural stability and ease of manufacture.
3Device complexity
If conventional carbon-based materials are used, then the electrode structure is simple, but the life characteristics are unsatisfactory
Solution Approach 1:
The composite structure of hard carbon and metal particles improves life characteristics by combining the structural stability of hard carbon with the high capacity and good cycle stability of metal particles. This composite approach enhances the overall durability and cycle life of the electrode without significantly increasing device complexity, as the materials can be mixed and processed using conventional electrode manufacturing techniques.
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 solution improves charging/discharging characteristics, life, and initial efficiency of sodium secondary batteries by increasing reversible capacity and reducing initial irreversible capacity.
Implementation Method 1
mixing a hard carbon having a specific surface area of about 50 square meters per gram (m2/g) or less and a ratio of a D-band peak intensity to a G-band peak intensity of about 1 or less, when analyzed by Raman spectroscopy, with a component including at least one selected from a Group 1 element, an oxide of a Group 1 element, a Group 2 element, an oxide of a Group 2 element, an element of Groups 13 to 16, an oxide of an element of Groups 13 to 16, and an oxide of an element of Groups 3 to 12
Implementation Method 2
a complex including a hard carbon having a specific surface area of about 50 square meters per gram (m2/g) or less and a ratio of a D-band peak intensity to a G-band peak intensity of about 1 or less when analyzed by Raman spectroscopy; and a component including at least one selected from a Group 1 element, an oxide of an a Group 1 element, a Group 2 element, an oxide of a Group 2 element, an element of Groups 13 to 16, an oxide of an element of Groups 13 to 16, and an oxide of an element of Groups 3 to 12
Implementation Method 3
a negative electrode is capable of sodium intercalation and deintercalation
Implementation Method 4
a negative electrode active material comprising a hard carbon with a specific surface area of 50 m2/g or less and a D-band to G-band peak intensity ratio of 1 or less, combined with elements from Group 1, Group 2, or Groups 13 to 12, enhances reversible capacity
Data Source
AI summary
A negative electrode active material for a non-lithium secondary battery, the negative electrode active material including a complex including a hard carbon having a specific surface area of about 50 square meters per gram or less and a ratio of a D-band peak intensity to a G-band peak intensity of 1 or less when analyzed by Raman spectroscopy; and a component including at least one selected from a Group 1 element, an oxide of a Group 1 element, a Group 2 element, an oxide of a Group 2 element, an element of Groups 13 to 16, an oxide of an element of Groups 13 to 16, and an oxide of an element of Groups 3 to 12.