Unbiased, complete solar charging of a neutral flow battery by a single Si photocathode

Wedege, Kristina; Bae, Dowon; Dražević, Emil; Mendes, Adélio; Vesborg, Peter Christian Kjærgaard; Bentien, Anders

doi:10.1039/c8ra00319j

Cited by 39 publications

(77 citation statements)

References 41 publications

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“…1a, the combination of the carbon with the TiO 2 resulted in a substantial negative shift in V on (~0.9 V). Further, the TiO 2 film with co-catalysts showed an efficient charge transfer performance, which is proven for water reduction studies 1,16 ; thus, this unexpected poor activity in ferricyanide reduction cannot be explained by a conductivity investigation.…”

Section: Resultsmentioning

confidence: 89%

“…1b). In present work, Pt and carbon are chosen as conducting materials since those have proven to be effective on the photoelectrode surface for the redox reaction 16,20,22,23 . Particularly, the carbon is favourable for the redox chemical cells since the noble metals, including Pt, can lead to an unexpected catalytic reaction, such as hydrogen evolution (HER), which can build an internal gas pressure and, consequently, potential mechanical damage on the system.…”

Section: Resultsmentioning

confidence: 99%

“…Previously, we demonstrated functional redox flow batteries consisting of ferri-/ferrocyanide, coupled with TEMPO-sulphate and NH 4 Br 16,17 ; thus, the same electrolyte conditions were used in this work. Cu 2+/+ redox couples were additionally added as a means of obtaining a higher cell voltage than that with TEMPOsulphate.…”

Section: Photoelectrochemical Behaviour and Efficiency Loss Analysismentioning

confidence: 99%

“…Unlike conventional PEC fuel conversion processes, SRFB offers flexibility with respect to redox potential, which results in an unprecedented wide selection of band-gap (E g ) of PEC materials. McKone et al 6 and other researchers 16,17 have shown meaningful conversion efficiencies using small band-gap semiconductors, such as c-Si (1.12 eV) and c-WSe 2 (1.2 eV). Further, general charging/ discharging reactions in RFB present facile kinetics, which can be several orders of magnitudes faster than other electrolysis technologies that require high overpotential 18 .…”

mentioning

confidence: 96%

“…Despite these advantages of redox batteries, SRFB studies are confronted with slow kinetics at the photoelectrode surface, which is opposite to the trend in RFB studies. Wedege et al 16 demonstrated a c-Si photocharging device with the Pt conducting layer showing an overpotential of~400 mV at 10 mA cm −2 for reduction of Fe (CN) 6 3− in NH 4 Cl electrolyte, whereas only approximately 130 mV was required for water reduction at the same pH using the same device. Cheng et al 19 also reported a dual-bed type SRFB using a combination of Ta 3 N 5 and Si-based devices, which exhibited overpotentials of approximately 300 mV and 400 mV, respectively.…”

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confidence: 99%

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Design principles for efficient photoelectrodes in solar rechargeable redox flow cell applications

et al. 2020

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Recent advances in photoelectrochemical redox flow cells, such as solar redox flow batteries, have received much attention as an alternative integrated technology for simultaneous conversion and storage of solar energy. Theoretically, it has been reported that even singlephoton devices can demonstrate unbiased photo-charging with high solar-to-chemical conversion efficiency; however, the poor redox kinetics of photoelectrodes reported thus far severely limit the photo-charging performance. Here, we report a band alignment design and propose surface coverage control to reduce the charge extraction barrier and create a facile carrier pathway from both n-and p-type photoelectrodes to the electrolyte with the respective redox reaction. Based on these observations, we develop a single-photon photocharging device with a solar-to-chemical conversion efficiency over 9.4% for a redox flow cell system. Along with these findings, we provide design principles for simultaneous optimisation, which may lead to enhanced conversion efficiency in the further development of solarrechargeable redox flow cells.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Photoelectrochemical Behaviour and Efficiency Loss Analysismentioning

confidence: 99%

mentioning

confidence: 96%

mentioning

confidence: 99%

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Design principles for efficient photoelectrodes in solar rechargeable redox flow cell applications

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Microbially Charged Redox Flow Batteries for Bioenergy Storage

Santos

Peixoto

Dias-Ferreira

et al. 2019

Bioelectrochemical Interface Engineering

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A Long Lifetime Aqueous Organic Solar Flow Battery

Kerr

Goulet

et al. 2019

Advanced Energy Materials

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The monolithic integration of solar energy conversion and electrochemical energy storage offers a practical solution to provide uninterruptable power supply on demand regardless of the ebb and flow of solar irradiation. Although connecting photovoltaics (PVs) with batteries, as adopted by some solar farms nowadays, [1] can provide the same uninterrupted power supply, the high capital cost and large footprint of two separate devices limit the market cases feasible for this option. [2] In contrast, integrated solar energy conversion and storage may represent a more compact, efficient, and cost-effective approach for off-grid electrification. [3] Among the many different types of "solar rechargeable battery" devices that have been reported [3,4] since the first demonstration in 1976, [5] integrated solar flow batteries (SFBs) hold great promises for practical applications because the solar component shares the same liquid electrolyte as the energy storage component, [6] which is based on redox flow batteries (RFBs) and can be easily scaled up. [2b] Despite the significant progress, most of such integrated devices suffer from some common scientific and technical issues. [4a,7] The first question one typically asks about any "solar device" is the efficiency. Due to the intrinsic efficiency limits of the solar energy conversion components and the working voltage mismatch between the solar energy conversion component and electrochemical energy storage component, the round-trip efficiency (i.e., solar-to-output electricity efficiency, SOEE) of most previously reported solar rechargeable devices rarely exceeded 5%. [3a,4a,7,8] It was recently demonstrated that by monolithically integrating III-V tandem junction solar cells with properly voltage matched RFBs, the integrated SFB device can deliver a SOEE of 14.1%. [9] Importantly, this comprehensive study [9] also revealed a set of general design principles that can further boost the SFB's efficiency. Primary among them is that the formal potential difference of selected redox couples needs to be closely matched with the photovoltage of the photoelectrodes at the maximum power point. Although III-V tandem junction solar cells can enable unprecedented high SOEE, the manufacturing cost for them ($40 W −1 to over $100 W −1 ) [10] is too high for practical applications. The most widely produced crystalline silicon-based solar cells have the cost of $0.15 to $0.25 W −1 after decades of research and commercial deployment, [10] thus are a good candidate for practical SFBs owing to its high abundance and decent PV efficiency.Monolithically integrated solar flow batteries (SFBs) hold promise as compact stand-alone energy systems for off-grid solar electrification. Although considerable research is devoted to studying and improving the round-trip efficiency of SFBs, little attention is paid to the device lifetime. Herein, a neutral pH aqueous electrolyte SFB with robust organic redox couples and inexpensive silicon-based photoelectrodes is demonstrated. Enabled by the excellent ...

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Unbiased, complete solar charging of a neutral flow battery by a single Si photocathode

Abstract: Solar redox flow batteries have attracted attention as a possible integrated technology for simultaneous conversion and storage of solar energy.

Cited by 39 publications

References 41 publications

Design principles for efficient photoelectrodes in solar rechargeable redox flow cell applications

Design principles for efficient photoelectrodes in solar rechargeable redox flow cell applications

Microbially Charged Redox Flow Batteries for Bioenergy Storage

A Long Lifetime Aqueous Organic Solar Flow Battery

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