Boron-Cleaned Cathode Active Material for Stable Lithium Content
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Solution Overview
Problem
Lithium secondary batteries face issues with non-uniform chemical structures due to lithium precipitation, leading to reduced capacity and life-span stability, and existing impurity removal methods can damage the cathode active material's structure during charging and discharging.
Innovation Solution
A method involving the use of a boron compound cleaning solution, such as boric acid, to clean and form a boron coating or doping on lithium metal oxide particles, enhancing surface stability and impurity removal while maintaining high lithium content, thereby improving structural and electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water washing is used to remove lithium salt impurities, then impurity removal is achieved, but particle surface is damaged and sufficient impurity removal cannot be implemented
Solution Approach 1:
The patent changes the chemical parameter of the cleaning solution from pure water to a boron compound-containing solution (0.1-5 wt% boric acid). This parameter change enables effective lithium salt impurity removal through chemical interaction while the boron compound forms a protective layer that prevents particle surface damage during the cleaning process.
2Duration of action of stationary object
If lithium metal oxide structure is deformed or damaged during repeated charging and discharging, then capacity retention deteriorates, but structural stability is required for long life-span
Solution Approach 1:
The patent applies preliminary action by performing boron compound treatment on the lithium metal oxide particles before battery assembly. This creates a protective coating or doping effect in advance that prevents structural deformation and damage during subsequent repeated charging and discharging cycles, thereby maintaining both structural stability and extending battery life-span.
Solution Approach 2:
The patent creates a composite structure by incorporating boron compounds into or onto the lithium metal oxide particle surfaces. This composite material approach enhances the structural stability of the cathode active material, preventing deformation during electrochemical cycling and improving capacity retention over extended periods.
3Reliability
If boron compound cleaning solution is used to clean lithium metal oxide particles, then impurity removal and surface stability are improved, but additional processing steps are required
Solution Approach 1:
The patent merges the cleaning function with the surface treatment function into a single integrated process step. The boron compound-containing cleaning solution simultaneously removes lithium salt impurities and applies a protective boron layer to the particle surfaces, eliminating the need for separate cleaning and surface treatment steps.
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 boron coating or doping improves the lithium secondary battery's capacity, power retention, and life-span stability by effectively removing impurities and preventing excessive capacity reduction, while maintaining high lithium content and structural integrity.
Implementation Method 1
The preliminary lithium metal oxide particle may be cleaned using a boron compound cleaning solution
Implementation Method 2
a boron compound cleaning solution, such as boric acid, to clean and form a boron coating or doping on lithium metal oxide particles
Implementation Method 3
form a boron coating or doping on lithium metal oxide particles, enhancing surface stability
Data Source
AI summary
In a method of manufacturing a cathode active material for a lithium secondary battery, a preliminary lithium metal oxide particle is prepared. The preliminary lithium metal oxide particle is cleaned using a boron compound cleaning solution. A cathode active material for a lithium secondary particle includes a lithium metal oxide particle where a ratio of a B+ peak intensity relative to a sum of peak intensities of Li+, B+ and LiB+ fragments by a TOF-SIMS analysis is in a range from 0.03% to 1.5%.