Solid-State Battery Base Film for Crystallinity Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thin-film-type solid-state secondary batteries face challenges in charge and discharge characteristics, cycle reliability, safety, and cost, particularly due to limitations in crystallinity of the positive electrode active material layer, which can be affected by the material of the current collector or substrate, and conventional lithium-ion batteries using liquid electrolytes pose risks of leakage and ignition.
Innovation Solution
A solid-state secondary battery structure is developed with a base film having conductivity and similar interatomic distances to the positive electrode active material layer, enhancing crystallinity through aligned crystal orientations, using materials like titanium nitride for the base film and lithium cobaltate, and incorporating a positive electrode current collector layer with the same metal, to achieve high charge and discharge capacity and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal treatment at high temperatures is applied to increase crystallinity of positive electrode active material layer, then charge and discharge capacity is improved, but manufacturing complexity increases and may be difficult depending on material of current collector or substrate
Solution Approach 1:
A base film is introduced as an intermediary layer between the positive electrode current collector layer and the positive electrode active material layer. This base film serves as a mediator that promotes crystallinity of the active material layer without requiring high-temperature thermal treatment, thereby simplifying the manufacturing process while maintaining improved charge and discharge capacity.
Solution Approach 2:
The base film is formed in advance before depositing the positive electrode active material layer. This preliminary action prepares the substrate surface with appropriate crystal structure and conductivity, enabling the subsequent active material layer to develop high crystallinity during deposition without requiring additional high-temperature processing steps.
2Ease of operation
If liquid electrolyte solution is used in lithium-ion secondary batteries, then ion transport is enabled, but safety risks increase due to decomposition reaction and liquid leakage
Solution Approach 1:
The invention changes the physical state parameter of the electrolyte from liquid to solid. By using a solid electrolyte instead of a liquid electrolyte solution, the battery maintains ion transport capability while eliminating the safety risks associated with liquid leakage and thermal decomposition of organic solvents.
Solution Approach 2:
The invention converts the potential harm of using electrolytes (liquid leakage and decomposition risks) into a benefit by selecting a solid electrolyte material that is inherently safer. The solid electrolyte eliminates the harmful liquid phase while maintaining the essential function of ion conduction, thereby converting a safety hazard into a safety advantage.
3Duration of action of moving object
If high-capacity secondary batteries are used to meet long-term usage requirements, then operational duration is improved, but device size and weight increase
Solution Approach 1:
The invention changes the physical state of the electrolyte from liquid to solid, enabling the use of solid electrolyte materials that offer higher energy density. This parameter change allows achieving high capacity and long operational duration with reduced weight and volume compared to conventional liquid electrolyte-based high-capacity batteries.
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 results in a solid-state secondary battery with improved charge and discharge capacity, cycle characteristics, and enhanced safety compared to conventional lithium-ion batteries, while allowing for flexible design and manufacturing advantages.
Implementation Method 1
a base film having conductivity and similar interatomic distances to the positive electrode active material layer, enhancing crystallinity through aligned crystal orientations
Data Source
AI summary
A solid-state secondary battery with high charge and discharge characteristics is provided. The solid-state secondary battery includes a first layer and a positive electrode active material layer over a substrate. The first layer and the positive electrode active material layer are in contact with each other; the first layer has conductivity; the first layer has a first crystal structure including first cations and first anions; the positive electrode active material layer has a second structure including second cations and second anions; and a value calculated by the following formula (1) is less than or equal to 0.1 when La denotes the minimum value of a distance between one of the first cations and another one of the first cations in the first crystal structure and Lb denotes the minimum value of a distance between one of the second cations and another one of the second cations.La-LbLa(1)