Cable-Shaped Alkali Metal-Sulfur Battery Design
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Solution Overview
Problem
Conventional lithium-sulfur and sodium-sulfur batteries face issues such as dendrite formation, low electric and ionic conductivities, rapid capacity decay, and low active material mass loading, which limit their energy density and cycle life, making them unsuitable for widespread commercialization.
Innovation Solution
A cable-shaped alkali metal-sulfur battery design featuring electrically conductive porous rods and layers with high porosity, allowing for increased active material loading and efficient ion transport, along with a pre-sulfurization method to deposit nano-scaled sulfur particles for enhanced sulfur utilization and reduced electron travel distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional lithium-sulfur and sodium-sulfur batteries use traditional electrode structures, then they can be manufactured with standard processes, but they suffer from low active material mass loading and limited energy density
Solution Approach 1:
The patent employs porous electrodes with high porosity (greater than 70%) to dramatically increase the surface area and volume available for active material deposition. The porous structure allows for much higher active material mass loading while maintaining electrical conductivity and ion transport pathways, directly resolving the contradiction between quantity of active material and structural complexity.
Solution Approach 2:
The patent implements a nested electrode configuration where one electrode is wrapped around another, creating a core-shell structure. This nesting approach maximizes the use of available volume for active material while maintaining a relatively simple manufacturing process, enabling high energy density without excessive structural complexity.
2Use of energy by moving object
If lithium metal anode is used in lithium-sulfur batteries to achieve high theoretical capacity, then specific energy increases, but dendrite formation occurs causing internal shorting and safety issues
Solution Approach 1:
The patent introduces a protective coating layer as an intermediary between the lithium metal anode and the electrolyte. This coating prevents direct contact and dendrite penetration while allowing ion transport, thereby maintaining the high specific energy of lithium metal without the safety risks of dendrite formation.
Solution Approach 2:
The patent modifies the surface properties of the lithium metal anode through chemical or physical treatment, changing parameters such as surface roughness, composition, or structure to suppress dendrite growth while preserving the high capacity benefits of lithium metal.
3Use of energy by moving object
If sulfur cathode material is used to achieve high theoretical capacity, then energy density increases, but electric and ionic conductivities remain low limiting rate capability
Solution Approach 1:
The patent uses porous electrode structures with optimized pore size distribution to enhance both the energy density and ion transport rate. The porous architecture provides numerous pathways for ion diffusion while maintaining high sulfur loading, effectively resolving the contradiction between energy density and rate capability.
Solution Approach 2:
The patent creates composite sulfur cathodes by combining sulfur with conductive materials such as carbon or metal oxides. This composite structure improves ionic and electronic conductivity while maintaining the high capacity of sulfur, enabling both high energy density and fast charge/discharge rates.
4Adaptability or versatility
If conventional rigid battery structures are used, then manufacturing is simplified, but adaptability to confined spaces and wearable devices is severely constrained
Solution Approach 1:
The patent employs flexible thin-film electrodes and separators that can be bent, folded, or shaped to conform to various geometries. This flexibility enables adaptation to confined spaces and wearable applications while maintaining relatively simple manufacturing processes through techniques like roll-to-roll fabrication.
Solution Approach 2:
The nested electrode configuration inherently creates a compact, flexible structure that can be easily integrated into various form factors. The wrapped architecture provides mechanical stability while maintaining flexibility, resolving the contradiction between adaptability and manufacturing ease.
5Use of energy by moving object
If sulfur cathode material is used, then theoretical capacity increases, but rapid capacity decay occurs during cycling due to polysulfide dissolution and shuttle effect
Solution Approach 1:
The patent converts the harmful polysulfide dissolution phenomenon into a beneficial effect by utilizing the dissolved polysulfides as reactive species that can be reduced at the lithium anode to form solid lithium polysulfide products. This approach, combined with protective coatings, prevents the shuttle effect while maintaining high capacity utilization, thereby extending cycle life.
Solution Approach 2:
The patent introduces protective coating layers as intermediaries between the sulfur cathode and electrolyte to prevent polysulfide dissolution and the associated shuttle effect. These coatings allow ion transport while blocking the harmful interactions that cause rapid capacity decay, enabling long cycle life with high theoretical capacity.
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 design achieves high volumetric and gravimetric energy densities, improved cycle life, and flexibility, overcoming the limitations of conventional batteries by enabling thicker electrodes with high active material mass loading and efficient sulfur utilization.
Implementation Method 1
electrically conductive porous rods and layers with high porosity, allowing for increased active material loading and efficient ion transport
Implementation Method 2
pre-sulfurization method to deposit nano-scaled sulfur particles for enhanced sulfur utilization
Implementation Method 3
The carbonaceous material absorbs lithium (through intercalation of lithium ions or atoms between graphene planes, for instance) and desorbs lithium ions during the re-charge and discharge phases
Data Source
AI summary
Provided is a process for producing a cable-shaped alkali metal-sulfur battery, comprising: (a) providing a first electrode comprising a conductive porous rod and a first mixture of a first electrode active material and a first electrolyte, wherein the first mixture resides in the pores of the porous rod; (b) wrapping around or encasing the first electrode with a porous separator to form a porous separator-protected structure; (c) wrapping around or encasing the porous separator-protected structure with a second electrode which comprises an electrically conductive porous layer and a second mixture of a second electrode active material and a second electrolyte, and the second mixture resides in pores of the porous layer; and (d) wrapping around or encasing the second electrode with a protective casing or sheath to form the battery; wherein either the first or the second electrode contains sulfur or a sulfur compound as a cathode active material.