Boron-Calcium Graphite Negative Electrode for High Capacity
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Solution Overview
Problem
Current lithium secondary batteries face limitations in increasing discharge capacity within the practical voltage range of 0 V to 2 V, which is essential for enhancing the cruising distance of electric vehicles.
Innovation Solution
A negative electrode active material composed of a graphite compound with a specific solid-solution ratio of boron and calcium, represented by the formula CaxByC1-y, where x and y satisfy certain inequalities, is developed to increase the discharge capacity by optimizing the cation storage and release mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional graphite materials are used as negative electrode active material, then the battery structure is simple and manufacturing is easy, but the discharge capacity is limited in the voltage range of 0 V to 2 V
Solution Approach 1:
The patent applies composite materials by combining graphite with specific amounts of boron (0.01-0.5 atom ratio) and calcium (0.01-0.1 atom ratio) to create a composite negative electrode active material. This composite structure enables the material to achieve higher discharge capacity in the 0-2 V range compared to conventional graphite, while the controlled addition of elements keeps the structural complexity manageable.
Solution Approach 2:
The patent changes the compositional parameters of graphite by precisely controlling the atom ratios of boron (0.01-0.5) and calcium (0.01-0.1). By adjusting these parameters within specific ranges, the discharge capacity is optimized for the 0-2 V voltage range, resolving the contradiction between capacity improvement and material complexity.
2Quantity of substance
If boron and metal elements are added to carbon material to increase capacity, then the discharge capacity increases, but the material composition becomes more complex and manufacturing difficulty increases
Solution Approach 1:
The patent optimizes manufacturing ease by defining specific parameter ranges for boron (0.01-0.5 atom ratio) and calcium (0.01-0.1 atom ratio). These controlled parameter changes enable capacity improvement while maintaining manufacturability, as the additions are within manageable limits for industrial production processes.
Solution Approach 2:
The patent applies local quality by introducing small, specific amounts of boron and calcium at controlled concentrations rather than uniform large-scale additions. This localized, precise element incorporation achieves the desired capacity enhancement while minimizing the impact on manufacturing complexity and process difficulty.
3Quantity of substance
If existing negative electrode materials are used, then the battery system is simple and reliable, but the cruising distance of electric vehicles cannot be sufficiently enhanced
Solution Approach 1:
The patent maintains performance stability by carefully controlling the atom ratios of added elements within specific ranges: boron (0.01-0.5) and calcium (0.01-0.1). These parameter changes are optimized to enhance discharge capacity in the 0-2 V range while ensuring the material structure remains stable and reliable for practical battery applications.
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 negative electrode active material achieves a higher discharge capacity in the voltage range of 0 V to 2 V, effectively addressing the capacity limitations of existing lithium secondary batteries.
Implementation Method 1
a carbon material or the like capable of storing and releasing lithium ions can be used as a negative electrode active material
Data Source
AI summary
A negative electrode active material contains a graphite material represented by a formula CaxByC1-y, where x and y satisfy 0<x<0.2 and 2x≤y≤0.5.