Positive Electrode Coating for High-Rate Discharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing non-aqueous electrolyte secondary batteries face challenges in enhancing high-rate discharge characteristics due to the formation of resistive films on the positive electrode active material, which inhibits lithium-ion intercalation/deintercalation reactions, especially when charging to high voltages.
Innovation Solution
A positive electrode configuration featuring a layered-structure lithium transition metal oxide with a rare-earth compound fixed on its surface and a tungsten-containing oxide in the mixture layer, which promotes lithium-ion permeability and conductivity, thereby enhancing high-rate discharge characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the charging voltage is increased to widen the voltage range and achieve higher battery capacity, then the battery capacity is improved, but the oxidizing power of the positive electrode active material increases causing decomposition of the electrolytic solution and formation of a resistive film that inhibits high-rate discharge
Solution Approach 1:
A coating layer comprising tungsten oxide and a rare-earth element compound is formed on the surface of the positive electrode active material particles. This coating layer acts as an intermediary between the active material and the electrolytic solution, preventing direct harmful interactions while allowing beneficial lithium ion transport. The coating layer suppresses electrolytic solution decomposition and prevents formation of resistive films, thereby enabling high-rate discharge while maintaining high battery capacity achieved through high voltage charging.
2Reliability
If a positive electrode active material containing lanthanum atoms in the surface is used to suppress decomposition reaction of the electrolytic solution, then the decomposition reaction is suppressed to some extent, but the high-rate discharge characteristics cannot be enhanced
Solution Approach 1:
The coating layer is composed of a composite material system combining tungsten oxide and a rare-earth element compound (such as lanthanum, cerium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or lutetium compound). This composite structure provides synergistic effects: the tungsten oxide component suppresses electrolytic solution decomposition, while the rare-earth element compound component enhances high-rate discharge characteristics by improving lithium ion conductivity. This composite approach overcomes the limitations of using lanthanum-containing material alone.
3Productivity
If the surface of a spinel lithium manganese oxide is modified with a tungsten-containing oxide to enhance high-rate discharge characteristics, then the high-rate discharge characteristics are enhanced, but charging to a high voltage results in formation of a resistive layer on the surface that prevents significant enhancement
Solution Approach 1:
The coating layer combines tungsten oxide with a rare-earth element compound to create a composite material that prevents the formation of resistive layers during high voltage charging. The rare-earth element compound component stabilizes the surface structure and prevents tungsten oxide from forming resistive layers, while maintaining the high-rate discharge enhancement benefits of tungsten oxide modification.
4Power
If the positive electrode active material contains transition metal that functions as a catalyst, then the electrochemical activity is improved, but a decomposition reaction of the electrolytic solution occurs forming a film that inhibits high-rate discharge
Solution Approach 1:
The coating layer comprising tungsten oxide and rare-earth element compound serves as an intermediary barrier between the transition metal-containing active material and the electrolytic solution. This coating layer suppresses the catalytic activity of transition metals toward electrolytic solution decomposition, preventing formation of harmful resistive films, while still allowing efficient lithium ion intercalation and deintercalation reactions to proceed.
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 combination of a rare-earth compound and tungsten-containing oxide on the surface of lithium transition metal oxide particles forms a thin, dense film with high stability and conductivity, significantly improving high-rate discharge characteristics by maintaining lithium-ion intercalation/deintercalation efficiency even at high voltages.
Implementation Method 1
particles of a layered-structure lithium transition metal oxide that have a rare-earth compound fixed on surfaces of the particles
Implementation Method 2
a tungsten-containing oxide, and a binder... promotes lithium-ion permeability and conductivity
Implementation Method 3
forms a thin, dense film with high stability and conductivity
Implementation Method 4
the lithium-ion intercalation/deintercalation reaction at the interface between the positive electrode active material and the non-aqueous electrolyte
Data Source
AI summary
An object is to provide a positive electrode for a non-aqueous electrolyte secondary battery and a non-aqueous electrolyte secondary battery that allow a high output characteristic. Included are a positive electrode collector and a positive electrode mixture layer formed on at least one surface of the positive electrode collector. The positive electrode mixture layer contains particles 3 of lithium nickel cobalt manganese oxide represented by LiNi0.55Co0.2OMn0.25O2, erbium oxyhydroxide 1 fixed on the surfaces of the particles of the lithium nickel cobalt manganese oxide 3, tungsten trioxide 2 adhering to the surfaces of the particles of the lithium nickel cobalt manganese oxide 3, and a binder.