Aqueous Sulfur Battery Separator for Scalable Energy Storage
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Solution Overview
Problem
Current energy storage technologies for renewable energy sources are costly, geographically limited, and lack scalability, particularly for intermittent energy sources like wind and solar, which require efficient and cost-effective solutions for transforming intermittent power into dispatchable electricity.
Innovation Solution
An electrochemical apparatus using an aqueous sulfur system with a catholyte and an anolyte separated by a permeable separator, where the catholyte contains a metal salt and the anolyte contains a polysulfide solution, facilitating oxygen generation and consumption during charging and discharging processes, respectively, to achieve low-cost and scalable energy storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional energy storage techniques (pumped hydroelectric storage and underground compressed air energy storage) are used, then cost is reduced (as low as around 100 US$/kWh), but geographical and environmental constraints limit deployment
Solution Approach 1:
The invention changes the fundamental parameters of energy storage by using aqueous electrolytes instead of requiring large-scale mechanical infrastructure. This allows the system to operate in space-constrained environments while maintaining low cost through the use of abundant, non-toxic materials like sulfur and aqueous solutions.
Solution Approach 2:
The invention replaces mechanical energy storage systems (pumped hydroelectric and compressed air) with an electrochemical system. This substitution eliminates the need for geographical features like elevation differences or underground cavities, enabling deployment in urban and space-constrained environments.
2Ease of manufacture
If sulfur is used as the electroactive material in the anolyte, then cost-per-stored-charge is minimized, but polysulfide dissolution and cross-membrane transport may occur
Solution Approach 1:
The invention introduces a specifically designed separator membrane as an intermediary between the catholyte and anolyte. This membrane is engineered to be selectively permeable, allowing metal cations to pass through while blocking polysulfide anions, thus preventing harmful cross-contamination while maintaining ionic conductivity for charge balance.
Solution Approach 2:
The invention employs a porous separator membrane with controlled pore size and charge characteristics. The porous structure allows selective ion transport based on size exclusion and electrostatic interactions, permitting metal cations to pass while retaining larger polysulfide anions, thereby solving the polysulfide dissolution problem.
3Ease of operation
If a separator permeable to metal ions is used, then ion transport is facilitated, but polysulfide cross-membrane transport may occur causing contamination
Solution Approach 1:
The invention applies local quality by creating a separator with spatially varying properties - specifically, a charged porous structure that exhibits size-selective and charge-selective permeability. The separator's local electrostatic field and pore architecture create different permeability characteristics for cations versus anions, allowing metal ion transport while blocking polysulfide passage.
Solution Approach 2:
The invention uses a composite separator structure combining porous matrix material with charged functional groups. This composite design integrates mechanical porosity for ion access with electrostatic charge for selective rejection of polysulfide anions, achieving both efficient metal ion transport and polysulfide containment.
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
This approach enables low-cost energy storage with high energy density, comparable to pumped hydroelectric storage and underground compressed air energy storage, while being scalable and deployable in space-constrained environments, with sulfur offering the lowest cost-per-stored-charge among electroactive materials.
Implementation Method 1
a separator disposed between the catholyte and the anolyte and permeable to the at least one metal ion
Implementation Method 2
the oxygen is consumed in the catholyte, the polysulfide oxidizes in the anolyte
Implementation Method 3
the polysulfide in the polysulfide solution undergoes a reduction reaction in the anolyte
Implementation Method 4
the at least one metal ion moves from the catholyte to the anolyte
Data Source
AI summary
An electrochemical apparatus includes a catholyte, an anolyte, and a separator disposed between the catholyte and the anolyte. The catholyte includes metal salt dissolved in water, thereby providing at least one metal ion. The anolyte includes a polysulfide solution. The separator is permeable to the at least one metal ion. During a charging process of the electrochemical apparatus, oxygen is generated in the catholyte, the polysulfide in the polysulfide solution undergoes a reduction reaction in the anolyte, and the at least one metal ion moves from the catholyte to the anolyte. During a discharging process of the apparatus, the oxygen is consumed in the catholyte, the polysulfide oxidizes in the anolyte, and the at least one metal ion moves from the anolyte to the catholyte.