Composite Cathode Shell for Stable Nickel-Rich Lithium Batteries
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Solution Overview
Problem
Nickel-based cathode active materials in lithium batteries suffer from degraded lifespan and poor thermal stability due to side reactions, leading to performance deterioration.
Innovation Solution
A composite cathode active material is developed, comprising a lithium transition metal oxide core coated with a shell of lithium nitrate and a conductive carbon-based composite, including a first metal oxide and carbon-based material, 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 and thermal stability deteriorate due to side reactions
Solution Approach 1:
A shell comprising lithium nitrate and conductive carbon-based composite is introduced as an intermediary layer between the nickel-based cathode active material and the electrolyte. This shell prevents direct contact and side reactions while maintaining ion conduction, thereby preserving lifespan and thermal stability without compromising the high capacity benefits of nickel-based materials
Solution Approach 2:
The invention creates a composite structure combining lithium nitrate and conductive carbon-based composite materials in the shell. This composite material provides both protective functions (preventing side reactions) and conductive functions (maintaining performance), resolving the contradiction between high energy density and reliability
2Reliability
If a protective coating is applied to prevent side reactions, then lifespan is improved, but ion conduction may deteriorate
Solution Approach 1:
The shell acts as an intermediary that is selectively permeable - it blocks harmful direct reactions between the cathode material and electrolyte while allowing lithium ion transport. This resolves the contradiction by providing protection without impeding the essential ion conduction process
Solution Approach 2:
The shell material composition and structure are optimized to achieve the right balance between protective function and ion conduction. By controlling the composition ratios and structural parameters of the shell, both lifespan improvement and maintained ion conduction are achieved
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, increases cycle characteristics, and maintains high-rate and lifespan performance of lithium batteries while preventing performance deterioration.
Implementation Method 1
a shell on and conformed to a surface of the core, wherein the shell includes lithium nitrate (LiNO3) and a conductive carbon-based composite
Implementation Method 2
a shell on and conformed to a surface of the core... capable of inhibiting a side reaction of the composite cathode active material
Data Source
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 on and conformed to a surface of the core, where the shell includes: at least one 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); a carbon-based material; and lithium nitrate, the at least one 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.