Cathode Additive Coating for Stable Lithium Secondary Batteries
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Solution Overview
Problem
Existing lithium secondary battery positive electrode materials face issues with stability due to side reactions with electrolyte liquids, leading to gas generation and reduced performance, particularly when using lithium transition metal oxides like LiCoO2, which also have high costs and thermal instability.
Innovation Solution
Incorporating an aluminum-doped lithium transition metal oxide, Li3PO4, Li5AlO4, and Li3BO3 as additives to form a coating layer on the lithium transition metal oxide, suppressing side reactions and improving battery stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium transition metal oxide (e.g., LiCoO2) is used as positive electrode active material, then high operating voltage and excellent capacity properties are achieved, but thermal stability deteriorates and cost increases
Solution Approach 1:
An additive layer comprising Li3PO4, Li5AlO4, and Li3BO3 is introduced as an intermediary between the lithium transition metal oxide active material and the electrolyte liquid. This additive layer acts as a protective mediator that prevents direct contact and harmful side reactions, thereby improving thermal stability and suppressing gas generation while allowing the high-voltage active material to function effectively
Solution Approach 2:
The positive electrode is constructed as a composite system combining the lithium transition metal oxide active material with a multi-component additive layer (Li3PO4-Li5AlO4-Li3BO3). This composite structure leverages the high voltage characteristics of the active material while the additive components work synergistically to provide thermal stability, electrochemical stability, and gas suppression
2Quantity of substance
If lithium transition metal oxide is used, then excellent capacity properties are achieved, but side reactions with electrolyte liquid occur causing gas generation and stability reduction
Solution Approach 1:
The additive layer serves as a protective intermediary that physically separates the lithium transition metal oxide from the electrolyte liquid, preventing harmful side reactions that would otherwise generate gas. This mediator layer allows ionic transport while blocking direct contact between incompatible materials
Solution Approach 2:
The patent converts the potentially harmful interaction between lithium transition metal oxide and electrolyte liquid into a beneficial controlled interface. By introducing the additive layer, the harmful side reactions are transformed into a controlled electrochemical environment where the additive components stabilize the interface and suppress gas-generating reactions
3Power
If LiCoO2 is used as positive electrode active material, then high operating voltage is achieved, but cost increases due to expensive material
Solution Approach 1:
The patent modifies the electrode composition parameters by introducing a multi-component additive system (Li3PO4, Li5AlO4, Li3BO3) in optimized proportions. This parameter change enables the use of high-voltage active materials while the additive components, which can be synthesized from abundant raw materials, reduce overall system cost and improve manufacturability
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 additive combination reduces gas generation and enhances battery stability, maintaining performance over multiple cycles and extended storage periods, thereby improving the overall efficiency and safety of lithium secondary batteries.
Implementation Method 1
Incorporating an aluminum-doped lithium transition metal oxide, Li3PO4, Li5AlO4, and Li3BO3 as additives to form a coating layer on the lithium transition metal oxide, suppressing side reactions
Implementation Method 2
an aluminum-doped lithium transition metal oxide
Data Source
AI summary
Provided is an additive for a positive electrode of a lithium secondary battery, the additive including a lithium transition metal oxide, Li3PO4, Li5AlO4 and Li3BO3. The lithium transition metal oxide has an aluminum-doped form. The additive including Li3PO4, Li5AlO4 and Li3BO3 together with the lithium transition metal oxide has functionality of improving stability of a battery when used in a positive electrode of a lithium secondary battery. Specifically, a general lithium transition metal oxide causes a side reaction with an electrolyte liquid when used in a positive electrode of a lithium secondary battery causing a problem of decreasing stability such as generating gas in the battery, however, the Li3PO4, the Li5AlO4 and the Li3BO3 are evenly mixed with the lithium transition metal oxide or some thereof form a partial coating layer, or a portion of aluminum is doped to the lithium transition metal oxide to suppress the lithium transition metal oxide from causing a side reaction with an electrolyte liquid.