Cathode Active Material Composition Conductive Polymer Coating
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Solution Overview
Problem
Lithium secondary batteries face limitations in conductivity, leading to reduced rate capability and stability, particularly with composite-based oxides having excessive lithium, which affects their performance and safety.
Innovation Solution
A cathode active material composition incorporating a composite of Chemical Formula xLi2MO3.(1−x)LiMeO2, a conductive polymer material, and a binder, which improves conductivity and stability, enhancing the battery's life characteristics, output characteristics, and rate capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If composite-based oxide with excessive lithium is used as cathode active material, then high capacity is achieved, but electrical conductivity decreases due to local structural changes
Solution Approach 1:
A conductive polymer coating is applied as an intermediary layer on the surface of the composite-based oxide particles. This conductive polymer acts as a mediator that compensates for the poor electrical conductivity of the oxide material, providing efficient electron transport pathways between particles and to current collectors, thereby resolving the conductivity issue while preserving the high capacity benefits of excessive lithium content.
Solution Approach 2:
The invention creates a composite structure where conductive polymer and binder materials are combined with composite-based oxide particles. This composite material approach allows the system to leverage the high capacity of the oxide while the polymer components provide the necessary electrical conductivity and structural stability, effectively combining the advantages of different material types.
2Power
If LiCoO2 is used as cathode active material, then high voltage operation is achieved, but crystal structure becomes unstable at voltage of 4.3 V or more
Solution Approach 1:
The invention modifies the operational parameters of LiCoO2 by applying a conductive polymer coating that enables stable operation at higher voltages (4.3 V or more). The polymer coating alters the electrochemical environment at the particle surface, allowing the material to maintain crystal structure stability under conditions that would normally cause degradation, thus enabling high voltage operation without sacrificing structural integrity.
3Use of energy by moving object
If LiCoO2 is used as cathode active material, then high energy density is achieved, but safety risk increases due to reaction with electrolyte solution
Solution Approach 1:
The conductive polymer coating creates an inert protective environment around the LiCoO2 particles, preventing direct contact and harmful reactions between the active material and the electrolyte solution. This protective layer acts as a barrier that maintains safety by eliminating the harmful interaction while allowing the underlying material to maintain its high energy density characteristics.
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 composition significantly improves conductivity, maintaining high capacity and stability, thereby enhancing the battery's performance and longevity, especially at high voltages.
Implementation Method 1
a cathode active material composition including: i) a composite of Chemical Formula 1, xLi2MO3.(1−x)LiMeO2 where 0
Data Source
AI summary
Provided are a cathode active material composition including an xLi2MO3.(1−x)LiMeO2 composite (where 0<x<1, and M and Me represent metal ions and may be the same or different from each other) and a conductive polymer material, and a secondary battery including the cathode active material composition in a cathode. Since the conductivity of the secondary battery of the present invention may be improved, the cathode active material composition may improve life characteristics, output characteristics, and rate capability of the secondary battery.