Composite-Coated Positive Electrode Material for High-Temperature Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face storage failure and degradation at high temperatures due to decomposition of electrolytes and damage to positive electrode materials, limiting their use to below 80°C, and existing solutions fail to adequately address thermal conductivity and safety hazards.
Innovation Solution
A positive electrode material is prepared by mixing aluminum tripolyphosphate with a ternary material and coating with colloidal silica sol, which enhances thermal stability and prevents decomposition, allowing storage at 80-85°C for over two months.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal oxide coating is used to protect positive electrode material, then high-temperature storage stability is improved, but ionic conductivity decreases and thermal conductivity is insufficient
Solution Approach 1:
The patent uses a composite coating system comprising colloidal silica sol and aluminum tripolyphosphate. The colloidal silica provides a glassy matrix with good ionic conductivity, while aluminum tripolyphosphate forms protective layers that enhance thermal stability. This composite approach allows the coating to simultaneously protect against thermal degradation while maintaining adequate ionic transport pathways.
Solution Approach 2:
The patent optimizes the composition ratios and concentration parameters of the coating materials. By adjusting the silica sol concentration, aluminum tripolyphosphate content, and coating thickness, the system achieves a balance between protective function and ionic conductivity. The sintering temperature and time parameters are also controlled to optimize the crystal structure and porosity of the coating layer.
2Stability of the object's composition
If metal oxide coating is used to protect positive electrode material, then structural stability is improved, but heat dissipation capability deteriorates
Solution Approach 1:
The colloidal silica coating forms a porous or micro-porous structure after sintering, which provides thermal pathways for heat dissipation while maintaining structural integrity. The porous structure allows heat to conduct through the coating layer more effectively than dense metal oxide coatings, preventing heat accumulation on the electrode surface.
Solution Approach 2:
The silica-aluminum composite coating acts as an intermediary thermal management layer between the positive electrode material and the electrolyte. It provides thermal stability to protect the electrode from degradation while its specific structure enables heat to be conducted away from the electrode, mediating between structural protection and thermal dissipation needs.
3Reliability
If hydroxypropyl guanidine gum is used as coating material, then high-temperature storage stability is improved, but organic substance carbonization occurs during sintering
Solution Approach 1:
The patent replaces the problematic organic hydroxypropyl guanidine gum with inorganic colloidal silica and aluminum tripolyphosphate. These inorganic materials do not undergo carbonization during sintering at typical battery processing temperatures (900-1100°C), eliminating the harmful side reactions while maintaining the protective coating function. The inorganic coating materials are thermally stable and do not decompose to form harmful substances.
4Quantity of substance
If LiPF6 is present in electrolyte at high temperature, then ionic conductivity is maintained, but decomposition occurs producing HF and PF5
Solution Approach 1:
The silica-aluminum composite coating is applied to the positive electrode surface before battery assembly and operation. This pre-formed protective layer acts as a barrier that prevents HF and PF5 (generated from LiPF6 decomposition) from reaching and attacking the electrode material. The coating neutralizes or blocks the harmful effects before they can cause damage, allowing LiPF6 to remain in the electrolyte for ionic conductivity without compromising electrode stability.
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 method effectively extends the storage life of lithium-ion batteries at high temperatures by preventing electrolyte decomposition and material damage, ensuring stable performance and safety.
Implementation Method 1
aluminum tripolyphosphate...can be hydrolyzed to generate triphosphate ions, which can effectively chelate metal ions on the surface
Implementation Method 2
the water-base silica sol Si(OH)4 in the positive electrode material provided by the present application can bond with the active oxygen on the surface of the positive electrode material
Implementation Method 3
ball-milling dry mixing...the nanoscale aluminum tripolyphosphate can be dispersed under the shear force of ball milling
Implementation Method 4
sintering the positive electrode material matrix obtained in step (3) to obtain the positive electrode material
Data Source
AI summary
Provided are a positive electrode material, a preparation method therefor and a use thereof. The positive electrode material comprises a ternary positive electrode material, aluminum tripolyphosphate and a binder. The preparation method comprises: (1) forming a positive electrode material pre-mixture by means of mixing reaction between aluminum tripolyphosphate and the ternary positive electrode material; (2) mixing a colloidal silica sol with the positive electrode material pre-mixture to form a positive electrode material mixture; (3) drying the positive electrode material mixture to obtain a positive electrode material matrix; and (4) sintering the positive electrode material matrix to obtain the positive electrode material. The positive electrode material can be used as a positive electrode material in a lithium-ion battery.