Cathode Composite Coating to Offset EDL in Lithium Batteries
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Solution Overview
Problem
Conventional positive electrode active materials for lithium secondary batteries face limitations in achieving high-output characteristics and surface stability due to the formation of an electric double layer (EDL) that hinders smooth intercalation and deintercalation of lithium ions, leading to degraded performance and reduced capacity.
Innovation Solution
A composite coating layer comprising a ferroelectric material and a boron-based oxide is formed on the surface of lithium composite transition metal oxide particles, offsetting the EDL and enhancing lithium ion mobility, thereby improving output characteristics, capacity, and surface stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional positive electrode active material is used, then the battery can operate, but an electric double layer forms on the surface that hinders smooth intercalation and deintercalation of lithium ions, degrading output characteristics
Solution Approach 1:
A composite coating layer comprising a ferroelectric material and a boron-based oxide is formed on the surface of the lithium composite transition metal oxide particles. This coating layer acts as an intermediary between the active material and the electrolyte, offsetting the harmful electric double layer effect while maintaining lithium ion intercalation and deintercalation functionality, thereby improving output characteristics
Solution Approach 2:
The surface properties of the positive electrode active material are modified by coating with a ferroelectric material and boron-based oxide. This changes the surface electrical characteristics and chemical composition, preventing electric double layer formation and enabling smooth lithium ion transport, thus enhancing output performance
2Quantity of substance
If the Ni content in NCM-based lithium composite transition metal oxides is increased to achieve high capacity, then capacity is improved, but side reactions such as oxygen desorption and electrolyte oxidation occur, increasing resistance and degrading lifetime characteristics
Solution Approach 1:
The composite coating layer serves as a protective intermediary between the high-Ni active material and the electrolyte, preventing direct contact and reducing side reactions such as oxygen desorption and electrolyte oxidation. This maintains both high capacity and improved lifetime characteristics
Solution Approach 2:
A composite coating layer comprising a ferroelectric material and a boron-based oxide is formed on the surface of the lithium composite transition metal oxide particles. This composite structure provides both protective functions (reducing side reactions) and functional benefits (maintaining lithium ion transport), enabling high capacity and improved lifetime characteristics simultaneously
3Productivity
If lithium cobalt oxide is used as the positive electrode active material, then high operating voltage and excellent capacity characteristics are achieved, but the price increases and supply becomes unstable due to cobalt scarcity
Solution Approach 1:
The composition of the positive electrode active material is changed from lithium cobalt oxide to nickel-cobalt-manganese-based lithium composite transition metal oxides with high Ni content. This compositional parameter change reduces cobalt dependence and supply risk while maintaining excellent capacity characteristics through optimized metal ratios
Solution Approach 2:
Lithium composite transition metal oxides containing Ni, Co, and Mn in specific ratios are used as the positive electrode active material. This composite material approach replaces expensive and scarce cobalt with more abundant nickel and manganese, reducing supply risk while maintaining high capacity characteristics
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 coating layer enables smooth intercalation and deintercalation of lithium ions, resulting in improved high-capacity and high-output characteristics, along with enhanced resistance and long-term stability of the battery.
Implementation Method 1
a composite coating layer including a ferroelectric material and a boron-based oxide containing boron formed on a surface of lithium composite transition metal oxide particles
Implementation Method 2
produce electrical energy through reduction and oxidation reactions occurring when lithium ions are intercalated into or deintercalated from the positive electrode and the negative electrode
Data Source
Figure 1
AI summary
Provided is a positive electrode active material for a secondary battery which includes a composite coating layer formed on a surface of lithium composite transition metal oxide particles, wherein the composite coating layer includes a ferroelectric material and a boron-based oxide containing boron.