Nonaqueous Battery Cathode Coating for Low DC Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nonaqueous electrolyte secondary batteries with nickel-based composite oxides face increased positive electrode resistance and DC resistance after repeated charging and discharging, leading to reduced output characteristics.
Innovation Solution
Incorporating a tungsten compound attached to the surface of nickel-based composite oxide particles and using an unsaturated sultone compound in the nonaqueous electrolyte to form a low-resistance film that protects the particles and suppresses tungsten elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-based composite oxide is used as positive electrode active material, then high capacity is achieved, but positive electrode resistance increases and DC resistance increases after repeated charging and discharging
Solution Approach 1:
The patent uses a composite oxide containing lithium and nickel (Li-Ni composite oxide) as the positive electrode active material. This composite material combines the high capacity benefits of nickel-based materials with the stability contributions from lithium, achieving both high capacity and improved resistance stability during cycling.
Solution Approach 2:
The patent applies tungsten compound coating specifically on the surface of the nickel-based composite oxide particles. This localized treatment modifies only the surface properties where electrochemical reactions occur, reducing positive electrode resistance and suppressing tungsten elution without altering the bulk material's high capacity characteristics.
2Reliability
If tungsten compound is attached on particles, then initial performance is improved, but tungsten elution occurs during repeated charging and discharging
Solution Approach 1:
The patent converts the potential harm of tungsten elution into a benefit by carefully controlling the tungsten compound coating. The tungsten layer that might otherwise dissolve is instead used to create a stable surface coating that prevents further elution, transforms the harmful dissolution process into a protective barrier formation.
Solution Approach 2:
The patent optimizes the tungsten compound content within specific ranges (0.01-0.5 atomic ratio W/Me, preferably 0.05-0.2) to achieve the right balance between initial conductivity and cycling stability. This parameter optimization prevents excessive tungsten elution while maintaining low initial resistance.
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 effectively suppresses the increase in DC resistance due to repeated charge and discharge cycles, maintaining high capacity and excellent output characteristics in nonaqueous electrolyte secondary batteries.
Implementation Method 1
Incorporating a tungsten compound attached to the surface of nickel-based composite oxide particles and using an unsaturated sultone compound in the nonaqueous electrolyte to form a low-resistance film
Implementation Method 2
a tungsten compound attached to a surface of the particles
Implementation Method 3
a nonaqueous electrolyte secondary battery including an unsaturated sultone compound in the nonaqueous electrolyte
Data Source
AI summary
A nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes a positive electrode material including particles of a composite oxide containing lithium and a metal Me other than lithium, and a tungsten compound attached to a surface of the particles. The metal Me contains at least nickel. The nonaqueous electrolyte includes an unsaturated sultone compound.