Lithium Battery Negative Electrode with Layered Organic Framework
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Solution Overview
Problem
Lithium secondary batteries with existing organic compounds as electrode active materials suffer from insufficient energy density and charge-discharge capacity, and the initial irreversible capacity is high due to reductive decomposition of the electrolytic solution during lithium intercalation.
Innovation Solution
A negative electrode with a layered structural body composed of an aromatic dicarboxylate anion-based organic framework and an alkali metal element layer, combined with fibrous and granular conductive materials, optimized in terms of specific surface area and particle size, to enhance charge-discharge characteristics and reduce initial irreversible capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If organic compounds with conjugated π-electron clouds are used as electrode active materials, then rapid charge-discharge capability is improved, but energy density remains insufficient
Solution Approach 1:
The patent uses composite organic compounds that combine conjugated π-electron cloud structures (for rapid charge-discharge) with specific molecular frameworks (for enhanced energy density). The composite structure integrates multiple functional components: conjugated systems for electron transport and molecular frameworks for lithium intercalation, achieving both fast kinetics and high energy density simultaneously
2Stability of the object's composition
If carbon materials such as graphite are used as negative-electrode materials, then structural stability is improved, but initial irreversible capacity increases due to electrolytic solution decomposition
Solution Approach 1:
The patent modifies the surface properties and electrochemical parameters of the negative electrode materials through controlled surface treatment and selection of specific organic compounds with appropriate redox potentials. This changes the interaction parameters between the electrode and electrolyte, reducing decomposition reactions while maintaining structural stability during cycling
3Productivity
If conjugated organic active materials are used to enable lithium intercalation, then charge-discharge capability is improved, but charge-discharge capacity remains insufficient
Solution Approach 1:
The patent transitions from two-dimensional planar conjugated structures to three-dimensional molecular frameworks with void spaces and channels. This dimensional expansion provides additional pathways and sites for lithium intercalation, simultaneously enhancing both charge-discharge kinetics and total capacity by utilizing spatial volume more effectively
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 the charge-discharge characteristics and stability of lithium secondary batteries by maintaining the crystal structure and reducing the decomposition of the ion-conducting medium, leading to enhanced initial discharge capacity and charge-discharge efficiency.
Implementation Method 1
an alkali metal element layer containing an alkali metal element which is coordinated with oxygen in the carboxylate anions to form a framework
Implementation Method 2
Lithium is coordinated with oxygen in the carboxylate anions to form a structural body
Data Source
AI summary
A negative electrode for a lithium secondary battery includes a negative-electrode active material having a specific surface area of Sx (m2/g) and an average particle size of Lx (μm), a fibrous conductive material having a specific surface area of Sy (m2/g) and an average length of Ly (μm), and a granular conductive material having a specific surface area of Sz (m2/g) and an average particle size of Lz (μm), in which letting the negative-electrode active material content be X, letting the fibrous conductive material content be Y, and letting the granular conductive material content be Z, Log((SyY+SzZ)/SxX×10−1)×Log((LyY+LzZ)/LxX×101) is defined as an electrode parameter, and the electrode parameter satisfies Log((SyY+SzZ)/SxX×10−1)×Log((LyY+LzZ)/LxX×101)≧0.