Crosslinked Cellulose Membranes for High-Power Salinity Gradient Energy
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Solution Overview
Problem
Current reverse electrodialysis devices for energy production from salinity gradients suffer from low electricity production capacity and high costs due to the use of expensive, potentially harmful membranes that are difficult to scale up, with membrane powers typically limited to a few W/m².
Innovation Solution
A device utilizing a membrane composed of a network of nanofibers and/or cellulose microfibers, which generates electrical energy from a salinity gradient, achieving powers on the order of kW/m², is developed. This membrane is made from a cellulosic material with a network of nanofibers and/or cross-linked cellulose microfibers, allowing for easy preparation and reduced environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional ion-exchange membranes are used in reverse electrodialysis devices, then selective ion transport is achieved, but membrane power output remains limited to a few W/m² and preparation costs are very high
Solution Approach 1:
The invention changes the fundamental parameters of the membrane material from conventional ion-exchange membranes to nanoporous membranes coated with boron nitride or titanium oxide. This material parameter change enables diffusion-osmosis phenomena within the pores, increasing membrane power output from a few W/m² to approximately 1 kW/m². The nanoporous structure with specific pore size distribution and hydrophobic/hydrophilic balance creates new transport mechanisms that dramatically improve power generation capability.
Solution Approach 2:
The invention uses composite material structures: nanoporous membranes coated with boron nitride or titanium oxide layers. This composite approach combines the porous substrate structure with functional coating materials to achieve both high power output and selective ion transport. The coating materials are deposited on the nanoporous surface to create a composite structure that maintains porosity while adding functional properties for enhanced energy generation.
2Power
If boron nitride or titanium oxide coated nanoporous membranes are used to achieve high membrane power output (kW/m²), then energy production per square meter increases, but preparation complexity and cost increase significantly and materials pose environmental risks
Solution Approach 1:
The invention replaces expensive, potentially harmful coating materials (boron nitride, titanium oxide) with more environmentally friendly and economical alternatives. The patent describes membranes with nanoporous structures that can be prepared using less hazardous materials, reducing environmental risks while maintaining the desired power output level. This substitution aligns with using more sustainable materials that are easier to handle and dispose of safely.
Solution Approach 2:
The invention creates a simplified version or copy of the high-performance membrane concept using different materials. Instead of directly using boron nitride or titanium oxide coatings, the patent develops membranes with comparable performance characteristics but using alternative materials that are less environmentally problematic. This allows achieving similar functional outcomes without the harmful aspects of the original material choice.
3Productivity
If conventional membranes are used, then device structure is simpler, but electricity production capacity is very low due to weak ionic conduction and high ohmic contribution
Solution Approach 1:
The invention employs nanoporous membranes as the core structural element to dramatically improve electricity production capacity. The nanoporous structure with controlled pore size distribution enables diffusion-osmosis phenomena, allowing ions to move through the membrane more efficiently. This porous architecture increases the active surface area and creates favorable pathways for ion transport, reducing ohmic losses and enhancing overall power generation capability from a few W/m² to approximately 1 kW/m².
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 device achieves high membrane power outputs of several hundred W/m², facilitating large-scale energy production at a lower cost and with reduced environmental risk, using economical and easy-to-prepare membranes.
Implementation Method 1
a membrane (10) separating the two reservoirs, said membrane comprising pores allowing the diffusion of electrolytes from reservoir A to reservoir B through said pore(s)
Implementation Method 2
Energy production from salinity gradients is one of the renewable energy sources with the greatest potential on a global scale
Data Source
Figure 1
Figure 2~3
AI summary
The present invention concerns a device for producing electrical energy, comprising: a) a first reservoir A (20A) for receiving an electrolyte solution (22A) having a concentration CA of a solute and comprising an electrode (30A) in contact with the electrolyte solution having concentration CA; b) a second reservoir B (20B) for receiving an electrolyte solution (22B) having a concentration CB of one and the same solute, CB being lower than CA, and comprising an electrode (30B) in contact with the electrolyte solution having concentration CB; c) a membrane (10) separating the two reservoirs, said membrane comprising pores allowing the electrolytes to diffuse from reservoir A to reservoir B through said pore or pores; and d) a device (32) capable of supplying the electrical energy generated by the potential difference existing between the two electrodes, characterized in that the membrane comprises at least one layer formed of a cellulosic material comprising a network of crosslinked cellulose nanofibres and/or microfibres.