Positive Electrode Coating Composition for Low-Resistance Pre-Doping
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Solution Overview
Problem
Current electric storage elements, such as lithium ion batteries and capacitors, face challenges in achieving high energy density, high output characteristics, and durability, with existing solutions experiencing issues like reduced energy density, inferior durability, and micro short-circuits due to gas generation during pre-doping in positive electrode active material layers.
Innovation Solution
A positive electrode precursor and coating liquid comprising a carbon material and lithium transition metal oxide, which promotes the decomposition of alkali metal compounds, reducing resistance and micro short-circuit rates, and enabling high-capacity, high-load charge/discharge cycles by pre-doping alkali metal ions efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacity positive electrode active material layers are used to increase energy density, then capacity increases, but micro short-circuits occur due to gas generation during pre-doping
Solution Approach 1:
The patent converts the harmful gas generation during pre-doping into a beneficial process by using the gas pressure to promote decomposition of alkali metal compounds. The gas bubbles generated during pre-doping are no longer seen as defects causing micro short-circuits, but as a mechanism that enhances alkali metal compound decomposition and improves overall electrode performance
Solution Approach 2:
The patent changes the chemical composition parameters of the positive electrode active material layer by incorporating specific ratios of carbon material (10-40 wt%), lithium transition metal oxide (5-30 wt%), and alkali metal compound (0.1-5 wt%). These parameter changes optimize the decomposition behavior during pre-doping, controlling gas generation to promote beneficial chemical reactions while preventing harmful micro short-circuits
2Productivity
If alkali metal compounds are added to promote pre-doping, then pre-doping efficiency increases, but resistance increases due to gas generation
Solution Approach 1:
The patent optimizes the concentration parameter of alkali metal compound within a specific range (0.1-5 wt%) to achieve the right balance. At this optimized concentration, the alkali metal compound decomposes efficiently during pre-doping to release alkali metal ions, promoting ion insertion without generating excessive gas that would increase resistance
Solution Approach 2:
The patent creates a composite positive electrode active material layer combining carbon material, lithium transition metal oxide, and alkali metal compound. This composite structure ensures that the alkali metal compound is distributed within a conductive matrix, maintaining low resistance while enabling efficient pre-doping through controlled decomposition
3Quantity of substance
If carbon material and lithium transition metal oxide are combined to increase capacity, then energy density improves, but decomposition control becomes difficult leading to micro short-circuits
Solution Approach 1:
The patent creates a multi-component composite material system where carbon material provides conductivity and structural stability, lithium transition metal oxide provides high capacity through lithium ion insertion/extraction, and alkali metal compound provides controlled decomposition behavior. The synergistic interaction of these components enables precise control over decomposition during pre-doping
Solution Approach 2:
The patent applies local quality by having the alkali metal compound distributed specifically within the composite matrix at controlled concentrations (0.1-5 wt%). This localized distribution ensures that decomposition occurs at beneficial locations within the electrode structure, promoting ion insertion while preventing micro short-circuits through controlled gas generation
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 solution provides a nonaqueous lithium electric storage element with enhanced capacity, low resistance, and improved durability by effectively pre-doping alkali metal ions, reducing micro short-circuit rates and maintaining high output characteristics across charge/discharge cycles.
Implementation Method 1
promotes the decomposition of alkali metal compounds, reducing resistance and micro short-circuit rates
Implementation Method 2
enabling high-capacity, high-load charge/discharge cycles by pre-doping alkali metal ions efficiently
Implementation Method 3
a nonaqueous lithium electric storage element with enhanced capacity, low resistance, and improved durability by effectively pre-doping alkali metal ions
Data Source
AI summary
Provided is a positive electrode precursor having a positive electrode active material layer, wherein the mass proportion A1 of a carbon material in the positive electrode active material layer accounts for 15-65 mass%, the mass proportion A2 of a lithium transition metal oxide in the positive electrode active material layer accounts for 5-35 mass%, the mass proportion A3 of an alkali metal compound in the positive electrode active material layer accounts for 10-50 mass%, A2/A1 is 0.10-2.00, A1/A3 is 0.50-3.00, and the positive electrode active material layer has a peel strength of 0.02-3.00 N/cm.