Ni-Rich Cathode Coating Process for Lower Cycling Resistance Growth
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Solution Overview
Problem
Existing Ni-rich electrode active materials in lithium ion batteries face undesired reactions on the surface, leading to electrolyte decomposition and high resistance growth upon cycling, which current coating methods fail to adequately address.
Innovation Solution
A process involving treatment with an aqueous medium containing heteropoly acids or compounds of Al or Sb, followed by thermal treatment, to deposit additional elements on the electrode active material surface, enhancing electrochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Ni-rich electrode active material is used to increase capacity, then energy density is improved, but surface reactions cause electrolyte decomposition and high resistance growth
Solution Approach 1:
The patent applies composite coating materials comprising at least two different inorganic compounds (such as metal oxides, metal hydroxides, metal carbonates, or metal phosphates) on the Ni-rich electrode active material surface. This composite structure provides synergistic protection: one component suppresses surface reactions and electrolyte decomposition while another maintains lithium exchange efficiency, thereby reducing resistance growth during cycling while preserving high energy density
Solution Approach 2:
The patent controls the thickness of the composite coating layer within specific ranges (0.1-5 μm preferably) and adjusts the compositional ratios of different inorganic compounds in the coating. By optimizing these parameters, the coating provides sufficient protection against surface reactions and electrolyte decomposition while maintaining adequate lithium ion conductivity, thus resolving the contradiction between energy density and resistance growth
2Object-affected harmful factors
If surface coating is applied to protect electrode material, then electrolyte decomposition is reduced, but lithium exchange may be hindered
Solution Approach 1:
The patent creates a composite coating with spatially distributed different inorganic compounds, where certain regions of the coating are optimized for protecting against electrolyte decomposition while other regions maintain higher lithium ion conductivity. This local differentiation allows simultaneous achievement of electrolyte protection and efficient lithium exchange without compromising either function
Solution Approach 2:
The composite coating structure incorporates porous characteristics that allow lithium ions to diffuse through the coating layer while the inorganic compounds provide protective barriers against electrolyte decomposition. The porosity ensures adequate lithium ion transport pathways are maintained, preventing hindrance to lithium exchange while still providing protective functionality
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 process results in Ni-rich electrode active materials with improved electrochemical performance, specifically reduced resistance growth during cycling.
Implementation Method 1
treating said particulate electrode active material with an aqueous medium that may contain a heteropoly acid or a compound of Al or Sb
Implementation Method 2
removing the water from step (b) at least partially
Data Source
AI summary
Described herein is a process for manufacturing a coated cathode active material including the steps of(a) providing a particulate electrode active material according to general formula Li1+xTM1−xO2, where TM is Ni,(b) treating said particulate electrode active material with an aqueous medium that may include a heteropoly acid or a compound of Al or Sb,(c) removing the water from step (b) at least partially,(d) optionally, adding at least one heteropoly acid or a compound of Al or Sb, as particulate compound or as aqueous solution or slurry,(e) optionally, treating the mixture from step (d) thermally,(f) adding at least one compound selected from the group consisting of B2O3, boric acid and lithium borates to the solid material obtained from step (e), if applicable, or from step (d) or (c), respectively, and(g) treating the residue obtained from step (f) thermally.