Core-Shell Cathode for High-Nickel Battery Stability
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Solution Overview
Problem
High-nickel content ternary materials used in lithium-ion batteries face issues such as non-stoichiometric formation, sensitivity to humidity, accelerated electrolyte decomposition, cracks, manganese ion elution, and low thermal stability, affecting battery performance, cycle life, and safety.
Innovation Solution
A core-shell structure is developed, comprising a core particle coated with an organic-inorganic composite layer that includes a nitrogen-containing hyperbranched polymer and an ion-conducting material like lithium-containing linear polymer or modified Prussian blue, enhancing ion and electron conductivity while protecting the core particle from electrolyte reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-nickel content ternary material is used to increase capacity and reduce cost, then battery capacity and cost-performance are improved, but structural stability and thermal stability deteriorate
Solution Approach 1:
A core-shell structure is employed where a thin film coating layer envelops the high-nickel cathode material core. This shell layer, composed of protective materials, maintains structural integrity while allowing the high-nickel core to deliver high capacity. The shell prevents direct exposure of the unstable high-nickel material to the electrolyte and environmental conditions, thereby resolving the contradiction between achieving high capacity through high nickel content and maintaining structural stability.
2Quantity of substance
If high-nickel content ternary material is used to increase capacity and reduce cost, then battery capacity and cost-performance are improved, but thermal stability deteriorates
Solution Approach 1:
The thin film coating in the core-shell structure serves as a thermal barrier and protective interface. This shell layer prevents direct thermal degradation of the high-nickel core material by isolating it from the electrolyte and external thermal stress, thereby maintaining thermal stability while preserving the high capacity characteristics of the high-nickel composition.
Solution Approach 2:
The core-shell structure creates a composite material system where the high-nickel core provides capacity and the protective shell provides thermal stability. This composite approach combines materials with complementary properties, allowing the battery to achieve both high capacity and improved thermal stability simultaneously.
3Quantity of substance
If high-nickel content ternary material is used, then battery capacity is improved, but chemical resistance deteriorates due to accelerated electrolyte decomposition
Solution Approach 1:
The thin film coating layer in the core-shell structure acts as a chemical barrier between the high-nickel cathode material and the electrolyte. This shell prevents direct chemical interactions that would otherwise lead to accelerated electrolyte decomposition and material degradation, thereby improving chemical resistance while maintaining the high capacity benefits of the high-nickel core.
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 core-shell structure improves the structural stability, chemical resistance, and thermal stability of the cathode material, leading to enhanced battery performance, extended life cycles, and increased safety, especially at high temperatures, by inhibiting surface reactions and phase changes.
Implementation Method 1
the organic-inorganic composite layer includes nitrogen-containinghyperbranched polymer and ion-conducting material
Implementation Method 2
an organic-inorganic composite layer formed on the surface of the core particle for encapsulating the core particle
Data Source
AI summary
An ion-conducting material, a core-shell structure containing the ion-conducting material, an electrode prepared with the core-shell structure and a metal-ion battery employing the electrode are provided. The core-shell structure includes a core particle and an organic-inorganic composite layer formed on the surface of the core particle for encapsulating the core particle. The core particle includes lithium cobalt oxide, lithium nickel cobalt oxide, lithium nickel cobalt manganese oxide, or lithium nickel cobalt aluminum oxide. Also, the organic-inorganic composite layer includes nitrogen-containing hyperbranched polymer and an ion-conducting material. The ion-conducting material is a lithium-containing linear polymer or a modified Prussian blue, wherein the modified Prussian blue has an ion-conducting group and the lithium-containing linear polymer has an ion-conducting segment.