Hard Carbon Electrode Material for Low-Potential Battery Capacity
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Solution Overview
Problem
There is a need to improve the capacity at low potential in batteries using hard carbon as an electrode active material.
Innovation Solution
An electrode active material comprising hard carbon with specific Raman spectrum characteristics, including a G′-band, G-band, and D-band ratios and half-widths, is used, along with a manufacturing method involving firing under an inert atmosphere with a trace amount of air to enhance the nano-graphite structure and structural defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional hard carbon is used as electrode active material, then the battery structure is simple and manufacturing is easy, but the capacity at low potential is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the firing atmosphere composition (inert gas with 0.1-10% oxygen), temperature (800-1500°C), and time to achieve specific Raman spectrum parameters (ID/IG ratio and D-band half-width) that correspond to optimized nano-graphite structure and structural defects, thereby improving low potential capacity
Solution Approach 2:
The patent creates a composite structure within the hard carbon by forming a core-shell configuration where the core contains nano-graphite crystallites with specific orientation and the shell contains controlled structural defects, achieving both high capacity and manageable manufacturing through a defined manufacturing process
2Quantity of substance
If the nano-graphite structure is enhanced to improve low potential capacity, then the G′-band intensity increases, but the manufacturing precision requirements increase
Solution Approach 1:
The patent establishes specific parameter ranges for the Raman spectrum (ID/IG ratio of 0.8-1.5 and D-band half-width of 80-150 cm⁻¹) that correspond to optimal nano-graphite structure, providing clear manufacturing targets that balance performance improvement with controllable precision
Solution Approach 2:
The patent uses Raman spectroscopy as a feedback mechanism to characterize the hard carbon structure after firing, allowing measurement of the ID/IG ratio and D-band half-width to verify whether the nano-graphite structure has been successfully formed, enabling process optimization and quality control
3Quantity of substance
If structural defects are increased to enhance capacity, then the D-band half-width changes, but the structural stability may deteriorate
Solution Approach 1:
The patent optimizes the D-band half-width parameter (80-150 cm⁻¹) to achieve the right balance between structural defects for capacity and structural stability, where the defects are sufficient to provide Na ion insertion sites but not so numerous as to compromise the overall hard carbon structure
Solution Approach 2:
The patent creates localized structural defects within the hard carbon matrix rather than uniform defects throughout, allowing regions with higher defect density for capacity while maintaining stable regions for structural integrity, as evidenced by the controlled D-band characteristics in the Raman spectrum
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 proposed electrode active material enhances battery capacity at low potentials, particularly in sodium ion batteries, by optimizing the graphene stacking and structural defects through precise Raman spectrum parameters and manufacturing conditions.
Implementation Method 1
firing to carbonize the raw material under an inert atmosphere comprising more than 0% and less than 1.0% of air
Data Source
AI summary
The present disclosure provides an electrode active material comprising hard carbon and capable of improving capacity at low potential and a manufacturing method therefor, an electrode mixture comprising such an electrode active material, and a battery comprising such an electrode mixture. The hard carbon comprised in the electrode active material of the present disclosure has a G′-band, a G-band, and a D-band in a Raman spectrum. The ratio IG′/IG of intensity IG, of the G′-band to intensity IG of the G-band is 0.05 or more. The half-width HwD of D-band is 50 or more and 160 or less. The method for manufacturing the electrode active material of the present disclosure comprises the following steps: providing a raw material comprising carbon, and firing to carbonize the raw material under an inert atmosphere comprising more than 0% and less than 1.0% of air.