Composite Cathode Coating for Nickel-Rich Cycle and Thermal Stability
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Solution Overview
Problem
Nickel-based cathode active materials in lithium batteries suffer from degraded lifespan characteristics and poor thermal stability due to side reactions, necessitating a solution to prevent or reduce battery performance deterioration.
Innovation Solution
A composite cathode active material is developed, comprising a core of lithium transition metal oxide coated with a shell containing lithium nitrate, conductive carbon-based composite, and first metal oxides, such as Al, Nb, Mg, Sc, Ti, Zr, V, W, Mn, Fe, Co, Pd, Cu, Ag, Zn, and Se, embedded in a graphene matrix, which enhances ion conduction and prevents side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nickel-based cathode active materials are used to achieve high capacity, then energy density is improved, but lifespan characteristics and thermal stability deteriorate due to side reactions
Solution Approach 1:
The patent applies composite materials by creating a core-shell structure where the core is lithium transition metal oxide (providing high capacity) and the shell contains lithium nitrate, conductive carbon-based composite, and first metal oxides embedded in graphene matrix. This composite structure allows the high-capacity nickel-based core to be protected by the stable shell, resolving the contradiction between achieving high energy density and maintaining reliability.
Solution Approach 2:
The patent uses a thin shell layer conforming to the core surface that acts as a protective barrier. This shell prevents direct contact between the nickel-based core and electrolyte, reducing side reactions while maintaining the high capacity benefits of the nickel-based material, thus improving lifespan characteristics without sacrificing energy density.
2Use of energy by moving object
If nickel-based cathode active materials are used to achieve high capacity, then energy density is improved, but thermal stability deteriorates due to side reactions
Solution Approach 1:
The composite structure combines nickel-based lithium transition metal oxide core with a shell containing lithium nitrate, conductive carbon-based composite, and first metal oxides in graphene matrix. This composite design provides thermal stability through the stable shell components while preserving the high energy density of the nickel-based core.
Solution Approach 2:
The thin shell layer acts as a thermal barrier and protective interface, preventing direct thermal and chemical interactions between the nickel-based core and electrolyte. This improves thermal stability while allowing the high-capacity core to function, resolving the contradiction between energy density and thermal stability.
3Reliability
If a shell is added to prevent side reactions, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent creates a composite cathode active material where the shell is not a separate component but is integrated with the core to form a unified composite structure. This approach improves reliability by preventing side reactions while avoiding the complexity of assembling separate shell and core components, as the composite is prepared as a single integrated material.
Solution Approach 2:
The patent merges the shell and core into a single composite cathode active material structure. The shell components (lithium nitrate, conductive carbon-based composite, first metal oxides in graphene matrix) are combined with the lithium transition metal oxide core to form an integrated composite, simplifying the overall device structure while maintaining the protective function.
4Adaptability or versatility
If multiple components are combined in the shell, then functionality is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent prepares the composite cathode active material as a single integrated composite through mechanical mixing and milling of all components (lithium transition metal oxide, lithium nitrate, conductive carbon-based composite, and first metal oxides in graphene matrix). This approach allows multiple functional components to be combined in the shell while avoiding the need for precise sequential coating operations, thus maintaining functionality without excessively increasing manufacturing precision requirements.
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 composite cathode active material improves the reversibility of electrode reactions, maintains high rate and cycle characteristics, and reduces internal resistance, leading to enhanced lithium battery performance.
Implementation Method 1
the shell includes lithium nitrate, LiNO3; and a conductive carbon-based composite
Implementation Method 2
a shell conformed to a surface of the core... capable of inhibiting a side reaction of the composite cathode active material
Implementation Method 3
mechanically milling the lithium transition metal oxide, the composite, and lithium nitrate
Data Source
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AI summary
A composite cathode active material, a cathode and a lithium battery that include the composite cathode active material, and a method of preparing the composite cathode active material are provided. The composite cathode active material includes: a core including a lithium transition metal oxide; and a shell conformed to a surface of the core, where the shell includes: lithium nitrate and a conductive carbon-based composite, the conductive carbon-based composite includes a first metal oxide represented by MaOb (where 0<a≤3, 0<b<4, and if a is 1, 2, or 3, and b is not an integer); and a carbon-based material; the first metal oxide is in a matrix of the carbon-based material, and M is at least one metal selected from among Groups 2 to 13, 15, and 16 of the Periodic Table of Elements.