Organic Coating for Lithium-Ion Cathode Plate
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Solution Overview
Problem
Lithium-ion batteries face performance degradation due to instability in the cathode crystal structure and oxidative decomposition of the electrolyte at high voltages, leading to reduced energy density and cycling performance, with existing inorganic coatings suffering from poor mechanical properties and uneven coverage.
Innovation Solution
A cathode plate with a cathode material comprising a cathode active material, binder, conductive agent, and an additive represented by structural formula I, which forms a flexible and uniform organic coating layer that protects the cathode active material, reducing side reactions and improving cycling and storage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If inorganic coating is employed to modify the cathode surface, then side reactions between cathode and electrolyte are reduced, but mechanical properties are poor resulting in cracking during cycling
Solution Approach 1:
The patent changes the chemical composition and physical state parameters of the coating material from inorganic to organic polymer, transforming the coating from brittle to flexible. This parameter change enables the coating to maintain mechanical integrity during cycling while providing protective functions.
Solution Approach 2:
The patent employs composite material strategy by combining organic polymer coating with cathode active material particles. The organic-inorganic composite structure leverages the flexibility of organic materials and the protective properties to create a coating that resists cracking while reducing side reactions.
2Reliability
If inorganic coating is applied to cathode surface, then cathode-electrolyte interface stability is improved, but coverage is uneven leading to abrupt capacity decrease
Solution Approach 1:
The organic polymer coating exhibits self-assembling and self-distributing properties during slurry preparation and drying processes. The polymer chains naturally distribute uniformly across cathode particles through steric stabilization and electrostatic repulsion, achieving homogeneous coverage without complex manufacturing controls.
Solution Approach 2:
The patent uses flexible organic polymer thin films that can conform to the surface morphology of cathode particles. These flexible films maintain uniform thickness and complete coverage by adapting to particle shapes and sizes, preventing the abrupt capacity decrease associated with uneven inorganic coating.
3Quantity of substance
If operating voltage is increased to improve energy density, then battery energy density increases, but cathode crystal structure stability deteriorates
Solution Approach 1:
The patent applies organic polymer coating beforehand to cushion and protect the cathode crystal structure from high-voltage-induced degradation. The coating acts as a protective buffer that mitigates structural collapse during charging-discharging cycles at elevated voltages, enabling sustained high energy density operation.
Solution Approach 2:
The organic coating provides preliminary anti-action by preemptively preventing the harmful interactions between high-voltage cathode surfaces and electrolyte. This preliminary protection stabilizes the cathode structure before degradation can occur, allowing the battery to operate at higher voltages without structural collapse.
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 cathode plate enhances the cycling and storage performance of lithium-ion batteries by forming a protective film on the cathode active material, reducing side reactions and maintaining mechanical integrity during long-term cycling, thereby improving energy density and high-temperature performance.
Implementation Method 1
surface coating of the cathode material is employed to reduce a side reaction between the cathode material and the electrolyte
Implementation Method 2
the additive including at least one compound represented by structural formula I, which is uniformly dispersed on the surface of particles of the cathode active material
Implementation Method 3
The organic coating layer formed by the compound represented by structural formula I has good mechanical properties, has some flexibility, has uniform coverage, can be effectively repaired during cycling of the battery
Implementation Method 4
coating the cathode slurry obtained in step (1) onto the surface of a cathode current collector
Implementation Method 5
adding and dispersing a cathode active material, a conductive agent, a binder, and an additive into a solvent to obtain a cathode slurry
Data Source
AI summary
Provided are a cathode plate of a lithium ion battery and a preparation method therefor and a lithium ion battery. The cathode plate comprises a cathode current collector and a cathode material located on the cathode current collector. The cathode material comprises a cathode active material, a binder, a conductive agent and an additive, wherein the additive comprises at least one of the compounds shown by structural formula I; and in structural formula I, the monomer of R is R1, R1 is an alkenyl compound or an ether compound containing an alkenyl, and n is a positive integer. The cathode plate contains a compound shown by structural formula I. The compound forms a protective layer on the surface of the particles of the cathode active material and reduces a side reaction between the cathode active material and an electrolyte at a high voltage.