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"Decoupled supercapacitive electrolyzer for membrane-free water splitting" (2024) https://www.science.org/doi/10.1126/sciadv.adi3180 https://www.science.org/do
by westurner 3y ago
"Decoupled supercapacitive electrolyzer for membrane-free water splitting" (2024)
https://www.science.org/doi/10.1126/sciadv.adi3180 https://www.science.org/doi/10.1126/sciadv.adi3180 :
> Abstract: Green hydrogen production via water splitting is vital for decarbonization of hard-to-abate industries. Its integration with renewable energy sources remains to be a challenge, due to the susceptibility to hazardous gas mixture during electrolysis. Here, we report a hybrid membrane-free cell based on earth-abundant materials for decoupled hydrogen production in either acidic or alkaline medium. The design combines the electrocatalytic reactions of an electrolyzer with a capacitive storage mechanism, leading to spatial/temporal separation of hydrogen and oxygen gases. An energy efficiency of 69% lower heating value (48 kWh/kg) at 10 mA/cm2 (5 cm–by–5 cm cell) was achieved using cobalt-iron phosphide bifunctional catalyst with 99% faradaic efficiency at 100 mA/cm2. Stable operation over 20 hours in alkaline medium shows no apparent electrode degradation. Moreover, the cell voltage breakdown reveals that substantial improvements can be achieved by tunning the activity of the bifunctional catalyst and improving the electrodes conductivity. The cell design offers increased flexibility and robustness for hydrogen production.
- westurner 3y agoAloe vera: > This type of supercapacitor formed within living plants acts as a form of electronic plant (e-plant) by using its tissue fluid electrolyte, which surprisingly presents a satisfying electrical capacitance of 182.5 mF cm−2, Hemp bast fiber: >> "Hemp Carbon Makes Supercapacitors Superfast" (2013) https://www.asme.org/engineering-topics/articles/energy/hemp-carbon-makes-supercapacitors-superfast https://www.asme.org/engineering-topics/articles/energy/hemp... : >> Hemp fiber waste was pressure-cooked (hydrothermal synthesis) at 180 °C for 24 hours. The resulting carbonized material was treated with potassium hydroxide and then heated to temperatures as high as 800 °C, resulting in the formation of uniquely structured nanosheets. Testing of this material revealed that it discharged 49 kW of power per kg of material—nearly triple what standard commercial electrodes supply, 17 kW/kg TMK there's not yet an aerogel electrode; but aerogels are porous. /? Hemp aerogel https://www.google.com/search?q=hemp+aerogel https://www.google.com/search?q=hemp+aerogel : "Superelastic and Ultralight Aerogel Assembled from Hemp Microfibers" (2023) https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.202300893 https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.202300... Hemp bast fiber is cheap: https://www.google.com/search?q=hemp+bast+fiber https://www.google.com/search?q=hemp+bast+fiber ?tbm=isch "Self-cleaning superhydrophobic aerogels from waste hemp noil for ultrafast oil absorption and highly efficient PM removal" (2023) https://www.sciencedirect.com/science/article/abs/pii/S1383586622020597 https://www.sciencedirect.com/science/article/abs/pii/S13835... : superhydrophobic and porous