Hard Carbon Composition for High-Capacity Battery Anodes
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Solution Overview
Problem
Current hard carbon materials used in secondary batteries have limitations in capacity, first coulomb efficiency, and rate performance due to high irreversible consumption of oxygen-containing functional groups and defects, which restrict their energy density and service life.
Innovation Solution
A hard carbon is developed with controlled oxygen-containing functional group content and structural defects, achieved through a specific thermal treatment process, reducing the probability of these groups bonding with active ions and optimizing interlayer spacing for improved ion transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hard carbon is used as negative electrode active material, then rapid intercalation and deintercalation of active ions is achieved, but capacity and first coulomb efficiency remain low
Solution Approach 1:
The patent applies parameter changes by precisely controlling the content of oxygen-containing functional groups (CO2 ≤ 1.0 mmoL/g, CO ≤ 2.0 mmoL/g) and structural defects in hard carbon material. This optimization balances the competing requirements: sufficient defects for rapid ion transport while limiting excessive functional groups that cause irreversible ion consumption, thereby achieving both high rate performance and high capacity
2Productivity
If oxygen-containing functional groups are present in hard carbon structure, then defects are provided for ion transport, but irreversible consumption of active ions increases
Solution Approach 1:
The patent applies partial action by controlling oxygen-containing functional groups to specific optimal ranges (CO2: 0.2-1.0 mmoL/g, CO: 0.5-2.0 mmoL/g) rather than eliminating them completely. This partial presence provides sufficient defects for ion transport channels while avoiding excessive functional groups that would cause severe irreversible ion consumption, achieving a balanced optimization
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 hard carbon exhibits enhanced capacity, first coulomb efficiency, and rate performance, with specific surface area and particle size optimization contributing to better energy density and cycling performance.
Implementation Method 1
an amount of generated CO2 is detected in thermal programmed desorption-mass spectrum (TPD-MS) to be less than or equal to 1.0 mmoL/g and an amount of generated CO is detected in thermal programmed desorption-mass spectrum to be less than or equal to 2.0 mmoL/g, when the hard carbon is heated from 50° C. to 1,050° C.
Data Source
AI summary
The present application provides a hard carbon, a method for preparing the same, a secondary battery comprising the same, and an electrical apparatus comprising the same, where an amount of generated CO2 is detected in thermal programmed desorption-mass spectrum (TPD-MS) to be less than or equal to 1.0 mmoL/g and an amount of generated CO is detected in thermal programmed desorption-mass spectrum to be less than or equal to 2.0 mmoL/g, when the hard carbon is heated from 50° C. to 1,050° C. The present application can improve both the capacity and the first coulomb efficiency of the hard carbon.