Multilayer Ni-Rich Cathode Coating for Cycle and Thermal Stability
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Solution Overview
Problem
Ni-based cathode active materials in lithium batteries face challenges with lifespan characteristics and thermal stability, leading to performance deterioration and side reactions with electrolytes.
Innovation Solution
A composite cathode active material is developed with a core of nickel-based lithium transition metal oxide coated with a multi-layered structure, including a first layer of a metal composition and a second layer containing phosphorus, which inhibits side reactions and improves surface stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Ni-based cathode active material is used to achieve high capacity and low cost, then capacity and cost are improved, but lifespan characteristics and thermal stability deteriorate
Solution Approach 1:
The patent applies composite materials by creating a core-shell structure where Ni-based cathode active material forms the core and is coated with a metal oxide shell. This composite structure allows the high-capacity Ni-based core to be protected by the stable metal oxide shell, resolving the contradiction between achieving high capacity and maintaining reliability.
Solution Approach 2:
The patent applies local quality by modifying only the surface region of the Ni-based cathode material with a metal oxide coating, while keeping the bulk composition unchanged. This localized modification preserves the high capacity properties of the Ni-based core while improving lifespan characteristics through the protective surface layer.
2Quantity of substance
If Ni-based cathode active material is used to achieve high capacity and low cost, then capacity and cost are improved, but thermal stability deteriorates
Solution Approach 1:
The patent uses composite materials by combining Ni-based cathode active material with a metal oxide shell. The metal oxide component provides enhanced thermal stability while the Ni-based core maintains high capacity, thus resolving the contradiction between capacity and thermal stability.
Solution Approach 2:
The patent applies local quality by concentrating the thermal stability enhancement in the surface coating layer while maintaining the high-capacity bulk composition. The metal oxide shell acts as a thermal barrier and stabilizer at the surface, preventing thermal degradation without affecting the electrochemical performance of the core.
3Reliability
If multi-layered shell structure is formed to prevent side reactions and improve stability, then lifespan characteristics and thermal stability are improved, but device complexity increases
Solution Approach 1:
The patent applies composite materials by forming a multi-layered shell structure consisting of different metal oxide layers. Each layer is designed to provide specific functions such as preventing Ni ion elution, reducing gas generation, and forming stable solid electrolyte interphase. This composite shell structure improves reliability while maintaining manageable complexity through systematic layer design.
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 enhances the cycle characteristics and thermal stability of lithium batteries by reducing Ni ion elution and gas generation, forming a stable artificial solid electrolyte interphase, and decreasing internal resistance.
Implementation Method 1
forming a stable artificial solid electrolyte interphase
Implementation Method 2
heat-treating the dried second composition at a temperature of about 400° C. to about 1000° C. under an oxidizing atmosphere
Data Source
AI summary
A composite cathode active material includes: a core including a plurality of primary particles; and a shell on the core, wherein the primary particles include a first lithium transition metal oxide comprising nickel, the shell includes a first layer and a second layer on the first layer, the first layer includes a first composition containing a first metal, the second layer includes a second composition containing phosphorus, and the first metal includes at least one or more metal, other than nickel, belonging to any of Groups 2 to 5 and Groups 7 to 15 of the Periodic Table of the Elements. Also a cathode, and a lithium battery each including the composite cathode active material, and a method of preparing the composite cathode active material.