Cathode Interface Layer for High Energy Density Accumulators
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Solution Overview
Problem
Current electrochemical accumulator technologies face challenges in achieving high specific energy density and specific power, with existing studies failing to provide satisfactory results for optimizing electrodes and electrolytes.
Innovation Solution
The development of an electrochemical accumulator cathode with a thin interface layer coated on a current collector, comprising a composition with a low content of conductive additives and a polymer-based binder, which improves adhesion and reduces contact resistance, allowing for enhanced energy density and power retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional electrode compositions with high conductive additive content are used, then electrical conductivity is improved, but energy density deteriorates due to increased inactive material mass
Solution Approach 1:
A thin interface layer (5-50 nm) composed of conductive polymer and inorganic nanoparticles is introduced as an intermediary between the current collector and the electrode active material. This interface layer serves as a mediator that provides electrical conductivity at the interface without requiring high conductive additive content in the bulk electrode composition, thereby resolving the contradiction between conductivity and energy density
Solution Approach 2:
The patent applies local quality by concentrating conductive materials specifically at the interface region where they are most needed for electron transport, rather than distributing them uniformly throughout the entire electrode. The interface layer contains conductive polymers and nanoparticles localized at the critical current collector-electrode boundary, while the bulk electrode maintains high active material content for energy storage
2Power
If thick interface layers are used to improve adhesion and reduce contact resistance, then electrical performance is improved, but mass energy density deteriorates due to increased inactive layer mass
Solution Approach 1:
The patent employs a thin film interface layer (5-50 nm) that provides the necessary electrical and mechanical functions without significant mass penalty. This thin film approach maintains adhesion and conductivity benefits while minimizing the mass of inactive material, thus resolving the contradiction between electrical performance and mass energy density
3Power
If high conductive additive content is used in electrode composition, then power delivery is improved, but capacity retention deteriorates due to material instability
Solution Approach 1:
The interface layer acts as a protective intermediary that stabilizes the interface between current collector and active material, preventing degradation reactions. This stable interface ensures long-term capacity retention while the conductive components in the interface layer maintain good power delivery capability
Solution Approach 2:
The interface layer is composed of a composite material system combining conductive polymers with inorganic nanoparticles. This composite structure provides both electrical conductivity for power delivery and chemical stability for capacity retention, resolving the contradiction between these two performance parameters
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 cathode design achieves improved energy density, capacity retention, and cyclability, with a 20% gain in capacity retention after 500 cycles and better performance at high operating rates, while maintaining low conductive additive content, thus enhancing the overall performance and lifespan of the accumulator.
Implementation Method 1
the interface layer is also in contact with the electrode and has a thickness of less than 5 μm
Implementation Method 2
a binder which makes it possible to ensure the cohesion of the particles, as well as adhesion to the substrate
Implementation Method 3
The positive and negative electrodes are immersed in the electrolyte which are the locus of electrochemical reactions
Implementation Method 4
The electrodes are, in particular, made of active materials for charging and discharging the ions via oxidation and reduction reactions
Data Source
AI summary
The present invention relates to composite material comprising a matrix and a metallic layer located at at least one surface of said composite material, said matrix comprising at least one polymer and a first population of particles of at least one electronically conducting metal, said layer comprising a second population of particles of at least one electronically conducting metal, a method for preparing such composite material and applications thereof.