Layered Lithium Cobalt Oxide Composition for Crystal Orientation Control
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Solution Overview
Problem
Existing methods for producing lithium cobalt oxide films do not provide control over the morphology and crystal orientation, which are crucial for achieving optimal electrochemical properties in lithium-ion batteries.
Innovation Solution
A composition comprising Co3O4 and crystalline lithium cobalt oxide is developed, where the crystalline oxide has specific atomic percentages of lithium and cobalt, and optionally dopant elements. This composition is formed through a method involving separate vapor sources for each component element, heated to react on a substrate, allowing for controlled crystal growth and orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to produce lithium cobalt oxide films, then the production process is simple, but the morphology and crystal orientation cannot be controlled
Solution Approach 1:
The production method is segmented into distinct stages: first forming a seed layer containing Co3O4, then depositing lithium cobalt oxide on top. This segmentation allows each layer to be optimized independently for specific crystal orientations and morphologies, resolving the contradiction between simplicity and controllability.
Solution Approach 2:
A seed layer containing Co3O4 is formed in advance before depositing the lithium cobalt oxide. This preliminary action establishes the desired crystal orientation and morphology framework, enabling precise control over the final film structure without complicating the overall production process.
2Manufacturing precision
If Co3O4 is introduced into lithium cobalt oxide, then crystal orientation and morphology are controlled, but the composition becomes more complex
Solution Approach 1:
Co3O4 is introduced locally in the seed layer rather than uniformly throughout the entire film. This localized introduction provides the necessary crystal orientation control at the interface while maintaining the compositional uniformity and stability of the bulk lithium cobalt oxide layer, resolving the contradiction between orientation control and compositional stability.
Solution Approach 2:
The invention creates a composite structure with a Co3O4-containing seed layer and a lithium cobalt oxide layer. This composite approach allows the Co3O4 to provide crystal orientation control while the lithium cobalt oxide maintains compositional stability, effectively resolving the contradiction between these two requirements.
3Stability of the object's composition
If lithium planes are aligned parallel to substrate, then the structure is stable, but lithium ion diffusion is restricted
Solution Approach 1:
The seed layer is prepared in advance with a specific crystal orientation that promotes favorable lithium plane alignment (perpendicular or at angles to the substrate). This preliminary structural arrangement enables fast lithium ion diffusion pathways to be established before the main lithium cobalt oxide layer is deposited, resolving the contradiction between structural stability and ion diffusion speed.
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 introduction of localized Co3O4 concentrations enables precise control over the morphology and crystal orientation of lithium cobalt oxide, resulting in improved electrochemical behavior, including enhanced capacity and cycle life in solid-state batteries.
Implementation Method 1
A lithium cobalt oxide film is formed on a substrate when the component elements react on the substrate to form a crystalline material. The depositions described in WO 2015/104539 were carried out in a physical vapor deposition (PVD) system
Implementation Method 2
heating a substrate to between about 30° C. and about 900° C.
Data Source
AI summary
Provided is a composition comprising: (a)a principal phase that is provided by a layered mixed metal oxide having a rocksalt structure belonging to the R-3m space group; the layered mixed metal oxide comprising the following component elements: 45 to 55 atomic % lithium; 20 to 55 atomic % of one or more transition metals selected from the group consisting of chromium, manganese, iron, nickel, cobalt, and combinations thereof; and 0 to 25 atomic % of one or more additional dopant elements selected from the group consisting of: magnesium, calcium, strontium, titanium, zirconium, vanadium, copper, ruthenium, zinc, molybdenum, boron, aluminium, gallium, tin, lead, bismuth, lanthanum, cerium, gadolinium and europium; wherein said atomic % is expressed as a % of total atoms of said layered oxide, excluding oxygen; (b)a minor phase that is provided by a metal oxide that does not have the crystal structure of the layered mixed metal oxide, the minor phase comprising one or more of the transition metals contained in the layered mixed metal oxide, the transition metals being selected from the group consisting of chromium, manganese, iron, nickel, and cobalt. Methods of making the composition and electrodes and cells, especially solid-state batteries, containing the composition are also provided. The rough morphology of the crystals confers advantages compared with smoother crystals of similar chemical composition, particularly in solid-state batteries.