Li-ion Cathode Oxygen Scavenger Coating for Thermal Stability
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Solution Overview
Problem
Lithium ion batteries face limitations such as oxygen-mediated thermal decomposition and performance decay due to cathode material instability and high cobalt content, which can lead to thermal runaway and reduced safety.
Innovation Solution
The use of a Li-containing oxide with an oxygen scavenger material, such as ZrO2 or CeO2, and a dopant like Ce or Y, in a layered cathode structure to absorb oxygen species and enhance thermal stability and reduce cobalt usage, while maintaining high energy density and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional cathode materials are used to achieve high energy density, then battery capacity is improved, but thermal stability deteriorates leading to oxygen-mediated thermal decomposition and thermal runaway
Solution Approach 1:
An oxygen scavenger coating layer is applied to the cathode material surface as an intermediary substance. This coating layer preferentially reacts with oxygen species released during thermal decomposition, preventing oxygen from reacting with organic solvents and vapors. The coating acts as a mediator that protects the bulk cathode material from thermal runaway while maintaining high capacity operation.
Solution Approach 2:
The invention converts the harmful oxygen release during thermal decomposition into a beneficial effect by having the oxygen scavenger coating consume the oxygen. The oxygen that would normally cause thermal runaway is instead captured by the coating material, transforming a dangerous byproduct into a protective mechanism that enhances thermal stability.
2Use of energy by moving object
If high cobalt content cathode materials are used to achieve high energy density, then battery capacity is improved, but safety and cost deteriorate due to thermal runaway risk and material cost
Solution Approach 1:
The invention changes the chemical composition parameters of the cathode material by applying a coating layer with specific oxygen scavenging properties. This coating modifies the surface chemistry without changing the bulk composition, allowing high-capacity materials to operate safely by controlling surface reactions that would otherwise lead to thermal runaway.
3Productivity
If repeated charging cycles are performed to utilize battery capacity, then energy throughput is improved, but performance deteriorates due to cathode material decay
Solution Approach 1:
The oxygen scavenger coating is applied in advance to the cathode material before cycling begins. This preliminary protective layer prevents oxygen release and subsequent degradation reactions during charging cycles, maintaining performance stability throughout the battery's operational life.
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 improved thermal stability, reduced risk of battery malfunction, and increased cycle life with higher discharge capacity and reduced irreversible capacity loss, making lithium ion batteries safer and more cost-effective.
Implementation Method 1
an oxygen scavenger material contacting at least a portion of the Li-containing oxide
Data Source
AI summary
An electrode material is provided to include a Li-containing oxide of the formula of Li(NixCoyMz)O2, wherein M is an element different from Li, Ni, Co, or O, wherein x, y, and z are each independently between 0 and 1 and the sum of x, y, z is 1; and an oxygen scavenger material contacting at least a portion of the Li-containing oxide. In another embodiment, the electrode material further includes a second Li-containing oxide having the formula of Li(Nix2Coy2Mz2)O2, wherein M is an element different from Li, Ni, Co, or O, wherein x2, y2, and z2 are each independently between 0 and 1 and the sum of x2, y2, z2 is 1, wherein the oxide composite is configured as a first material layer, wherein the second Li-containing oxide is configured as a second material layer disposed next to the first material layer.