Lithium Battery Positive Electrode Conductive Network Design
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in achieving high current density, improved cycle-life characteristics, and safety while maintaining energy density and cost-effectiveness, particularly at low temperatures and room temperature.
Innovation Solution
A positive electrode composition for rechargeable lithium batteries is developed, incorporating a combination of a positive active material, sheet-shaped conductive material, and spherically shaped conductive material, such as carbon black or acetylene black, to enhance electrical conductivity and adherence, thereby increasing current density and cycle-life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the current density of rechargeable lithium battery is increased to achieve high energy density per unit volume, then the energy density is improved, but the cycle-life characteristics deteriorate and safety issues arise
Solution Approach 1:
The patent uses a composite conductive material system combining sheet-shaped conductive material (graphene, flake-shaped carbon) and spherically shaped conductive material (carbon black, acetylene black) to create a dual-function conductive network that maintains electrode integrity at high current densities while improving cycle-life characteristics
Solution Approach 2:
The patent applies different shaped conductive materials to different functional requirements: sheet-shaped materials provide structural framework and adherence to current collector, while spherically shaped materials fill interstices and provide point-contact conductivity, creating localized functional zones within the electrode composition
2Reliability
If conventional conductive materials are used to improve electrical conductivity, then the current density increases, but the adherence to current collector and structural integrity deteriorate
Solution Approach 1:
The patent combines sheet-shaped conductive materials (which provide structural framework and strong adherence to current collector) with spherically shaped conductive materials (which provide point-contact conductivity and fill interstices), creating a composite network that simultaneously achieves high electrical conductivity and mechanical integrity
Solution Approach 2:
The patent introduces spherically shaped conductive particles (carbon black, acetylene black) with curved surfaces that can roll and conform to contact points, providing effective electrical pathways through the electrode matrix while the sheet-shaped materials maintain overall structural adherence to the current collector
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 composition achieves increased current density, improved cycle-life characteristics, and safety, with reduced swelling and higher energy density per unit volume, while maintaining effective electron movement and adherence to the current collector.
Implementation Method 1
a sheet-shaped conductive material and a spherically shaped conductive material... to enhance electrical conductivity and adherence, thereby increasing current density
Implementation Method 2
The positive electrode and the negative electrode may intercalate and deintercalate lithium ions and produce electrical energy through oxidation and reduction reactions
Data Source
AI summary
A positive electrode composition for a rechargeable lithium battery includes a positive active material, a spherically shaped conductive material, and a sheet-shaped conductive material. The spherically shaped conductive material is included in an amount of about 1.1 to about 10 parts by weight based on 1 part by weight of the sheet-shaped conductive material. A positive electrode includes the positive electrode composition and a rechargeable lithium battery includes the positive electrode.