Organic Ammonium Coated Lithium Battery Cathode
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Solution Overview
Problem
Lithium secondary batteries face issues with decreased residual and recovery capacity due to metal component dissolution and electrolyte decomposition during high-temperature storage, which existing methods like reducing active material surface area or surface treatment fail to adequately address without compromising discharge characteristics.
Innovation Solution
Incorporating an organic ammonium compound into the cathode or coating it on the separator to liberate ammonium ions, which inhibit metal ion precipitation and reduce electrolyte decomposition, thereby enhancing battery performance at high and low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the specific surface area of the active material is reduced to decrease metal element dissolution, then the dissolution is reduced, but the high-rate discharge characteristics and low-temperature characteristics deteriorate due to decreased reaction area and increased diffusion distance
Solution Approach 1:
The patent applies local quality by treating only the surface of the cathode active material particles with an organic ammonium compound solution, rather than changing the overall particle size. This surface treatment creates a localized protective layer that prevents metal element dissolution while maintaining the bulk particle structure and internal reaction pathways intact, thus preserving high-rate discharge characteristics.
Solution Approach 2:
The patent creates a composite structure by coating the cathode active material surface with an organic ammonium compound layer. This composite approach combines the bulk cathode material (maintaining electrochemical activity) with a surface coating layer (providing protective function), achieving both dissolution prevention and performance maintenance.
2Reliability
If surface treatment using heterogeneous elements is applied to improve high-temperature storage characteristics, then storage characteristics improve, but battery capacity severely decreases and multiple manufacturing processes are added
Solution Approach 1:
The patent changes the chemical parameters of the surface treatment by using organic ammonium compounds with specific functional groups (carboxyl, hydroxyl, or amino groups) instead of traditional inorganic heterogeneous elements. This parameter change in the treatment chemistry provides protection against metal element dissolution without the severe capacity loss associated with conventional surface treatments.
Solution Approach 2:
The patent extracts and eliminates the harmful effect of metal element dissolution from the system by applying a targeted surface treatment that specifically addresses this issue without requiring multiple complex manufacturing processes, thereby simplifying production while maintaining battery capacity.
3Reliability
If the specific surface area of the active material is reduced to decrease metal element dissolution, then the dissolution is reduced, but long-term heat treatment is required which increases manufacturing complexity
Solution Approach 1:
The patent applies preliminary action by performing surface treatment with organic ammonium compound during the cathode manufacturing process itself, rather than requiring separate post-processing steps. The surface treatment is integrated into the slurry preparation and coating stages, eliminating the need for additional long-term heat treatment processes.
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 use of organic ammonium compounds improves residual and recovery capacity and power retention in lithium secondary batteries after high-temperature storage, while maintaining or improving discharge characteristics.
Implementation Method 1
The organic ammonium compound can liberate ammonium ions which are capable of removing metal ions present in the electrolyte, such as manganese (Mn) ions
Implementation Method 2
forms a stable surface coating on the anode to thereby inhibit precipitation of metal ions
Implementation Method 3
Upon charging, lithium ions deintercalate from the cathode active material and intercalate into the carbon layer of the anode
Implementation Method 4
the non-aqueous electrolyte serves as a medium through which lithium ions migrate between the anode and the cathode
Data Source
AI summary
Disclosed is a secondary battery comprising a lithium transition metal oxide as a cathode active material, wherein an organic ammonium compound is added to a cathode and/or is coated on a separator. Therefore, the secondary battery according to the present invention can achieve improvements in residual capacity and recovery capacity even after high-temperature storage of the battery, simultaneously with improved power retention of the battery at low and high temperatures.