LiCoO2 Cathode Groove Orientation for Higher Battery Capacity
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Solution Overview
Problem
Current lithium ion batteries using LiCoO2 as a cathode active material face limitations in battery capacity and efficiency due to the alignment of crystal planes and ion conductivity during charge and discharge processes.
Innovation Solution
The battery design incorporates a cathode layer with crystal grains aligned in specific directions, featuring grooves that increase the surface area aligned with crystal directions, enhancing lithium ion diffusion and ionic conductivity, thereby improving battery capacity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If LiCoO2 is used as cathode active material with conventional crystal alignment, then battery can be manufactured with standard process, but battery capacity and efficiency are limited
Solution Approach 1:
The patent applies local quality by creating grooves with specific crystal orientations in localized regions of the cathode layer. The side surfaces of the grooves are formed with crystal grains having <100>, <110>, or <111> directions aligned perpendicular to the current collector, while other regions maintain conventional orientation. This localized modification of crystal orientation in groove regions enhances lithium ion diffusion and battery capacity without requiring complete restructuring of the entire cathode layer.
Solution Approach 2:
The patent introduces a new dimension by forming vertical grooves that extend from the upper surface toward the current collector. This three-dimensional groove structure creates additional side surfaces with optimized crystal orientations, adding a vertical dimension to the traditionally planar cathode layer. The grooves increase the effective surface area for lithium ion insertion and improve ion diffusion pathways in the thickness direction.
2Productivity
If grooves are formed in cathode layer to increase surface area, then lithium ion diffusion is enhanced, but manufacturing process becomes more complex
Solution Approach 1:
The patent creates a porous-like structure by forming grooves in the cathode layer. These grooves introduce void spaces and increased surface area that facilitate lithium ion diffusion. The groove structure resembles a controlled porous architecture that provides multiple pathways for ion transport, enhancing charge/discharge rates while maintaining structural integrity of the cathode layer.
Solution Approach 2:
The patent applies preliminary action by forming grooves in the cathode layer before final assembly and sintering processes. The grooves are created in the green state or precursor form of the cathode, allowing subsequent sintering to densify the material around the grooves while preserving the groove structure. This sequencing enables groove formation with reduced process complexity compared to post-assembly modification.
3Reliability
If crystal grains are aligned in specific directions, then ionic conductivity is improved, but control precision during manufacturing must be increased
Solution Approach 1:
The patent applies inversion by changing the approach to crystal orientation control. Instead of attempting to control the orientation of all crystal grains in the entire cathode layer, the invention focuses on creating grooves where the crystal grains along the groove side surfaces are oriented with specific directions (<100>, <110>, or <111>) perpendicular to the current collector. This inverted strategy of targeting localized groove regions rather than the whole layer reduces manufacturing precision requirements while achieving improved ionic conductivity where most needed.
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 enhanced alignment of crystal directions in the cathode layer increases battery capacity and efficiency, allowing for faster lithium ion diffusion and improved charge/discharge characteristics, suitable for devices requiring high power.
Implementation Method 1
enhancing lithium ion diffusion and ionic conductivity
Data Source
AI summary
A battery includes a cathode layer, a cathode current collector on the cathode layer, an anode layer on the cathode layer, an anode current collector on the anode layer, a separator between the cathode layer and the anode layer, and an electrolyte, wherein the cathode layer includes a plurality of crystal grains of a cathode active material and aligned in a first direction, and at least one groove formed in a direction perpendicular to an upper surface of the cathode layer that is in contact with the separator, and wherein a side surface of the cathode layer exposed by the at least one groove is aligned with a <101> crystal direction, a <hk0> crystal direction, wherein h and k are integers greater than or equal to 1, or a combination thereof, of the crystal grains of the cathode active material.