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Scheme of the integrated solar VRFB with the CIGS solar cells (A). The cell was assembled with a reference electrode in the negative side, close to the H-TiO 2 /CF. Cross-sectional view (B) of the electron transfer between the PV minimodule and the anode side.
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The integration of photovoltaics and vanadium redox flow batteries (VRFB) is a promising alternative for the direct conversion and storage of solar energy in a single device, considering their inherent higher energy density versus other redox pairs. However, this integration is not seamless unless the photovoltaic system is customized to the voltag...
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... recently, an organic solar RFB based on viologen-and ferrocene-derived redox couples with c-Si photoelectrodes has achieved a promising stable performance and solar round-trip energy efficiency of 5.4%, 33 attributed to the proper matching between the photoelectrodes and the redox pairs, moving a step forward into the development of more efficient systems. Based on this, we have carried out the integration of adapted CIGS (as "embedded" photoelectrodes) into VRFB without additional power electronics (Figure 1), by evaluating two mini-modules fabricated from commercial thin film PV, in two different battery configurations (symmetric V4/V4 and asymmetric V4/V3). These systems reach full unbiased photocharge with high overall round trip energy conversion efficiencies. ...
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... PV modules were sealed to avoid the contact with the electrolyte, with Optically Clear Double-Sided Adhesive Tape (THORLABS) and kapton® adhesive tape (Dupont). A scheme depicting the different steps is included in Figure S1. The final geometric areas of the 3CM and 4CM were 16 and 20.4 cm 2 . ...
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... "embedded" CIGS module was integrated by coupling on the negative side of the cell, between the PMMA window and the graphite current collector. Additionally a reference electrode (Ag/AgCl) was inserted into the negative side of the cell and the individual potentials vs reference were followed during tests ( Figure 1A). The individual potentials have been referred to the standard hydrogen electrode (SHE) by means of the expression: V SHE = V Ag/AgCl + 0.059·pH + 0.199V. ...
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... the photocharge experiment, the CIGS modules were illuminated at 0 V conditions with a PEC-L01 solar simulator (PECCELL Technologies, Inc) equipped with a 300W Xe arc lamp and AM 1.5G filter. A cross-sectional view with the PV minimodule configuration and the electron transfer to the anolyte can be found in Figure 1B. The irradiance was adjusted to 100 mW·cm -2 (1 Sun) using a silicon diode (XLPF12-3S-H2-DO; Gentec-EO). ...
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... the V4/V4 configuration was assessed, the electrolytes were substituted by fresh VO 2+ and V 3+ solutions in the catholyte and anolyte, respectively, in a regular full VRFB configuration. The cell was assembled as described in Figure 1 and a photocharge/discharge was evaluated. As seen in Figure S4, the variation of the cell potential during the photocharge remarkably matches the photocurrent of the PV system, which continuously drops with time as the SoC (i.e., cell potential) increases. ...
Citations
... The photovoltaic (PV) modules are directly integrated by stacking with the electrochemical module of RFBs that work autonomously. SRFB technology is in the research and development stage, and it is trying to overcome some of the disadvantages related to its lower capacity, material stability, and insufficient photo voltage [28,[250][251][252][253][254][255][256][257][258][259][260][261][262][263][264][265]. ...
Redox flow batteries represent a captivating class of electrochemical energy systems that are gaining prominence in large-scale storage applications. These batteries offer remarkable scalability, flexible operation, extended cycling life, and moderate maintenance costs. The fundamental operation and structure of these batteries revolve around the flow of an electrolyte, which facilitates energy conversion and storage. Notably, the power and energy capacities can be independently designed, allowing for the conversion of chemical energy from input fuel into electricity at working electrodes, resembling the functioning of fuel cells. This work provides a comprehensive overview of the components, advantages, disadvantages, and challenges of redox flow batteries (RFBs). Moreover, it explores various diagnostic techniques employed in analyzing flow batteries. The discussion encompasses the utilization of RFBs for large-scale energy storage applications and summarizes the engineering design aspects related to these batteries. Additionally, this study delves into emerging technologies, applications, and challenges in the realm of redox flow batteries.
... The photovoltaic (PV) modules are directly integrated by stacking with the electrochemical module of RFBs that work autonomously. SRFB technology is in the research and development stage, and it is trying to overcome some of the disadvantages related to its lower capacity, material stability, and insufficient photo voltage [28,[250][251][252][253][254][255][256][257][258][259][260][261][262][263][264][265]. ...
Redox flow batteries represent a captivating class of electrochemical energy systems that are gaining prominence in large-scale storage applications. These batteries offer remarkable scalability, flexible operation, extended cycling life, and moderate maintenance costs. The fundamental operation and structure of these batteries revolve around the flow of an electrolyte, which facilitates energy conversion and storage. Notably, the power and energy capacities can be independently designed, allowing for the conversion of chemical energy from input fuel into electricity at working electrodes, resembling the functioning of fuel cells. This work provides a comprehensive overview of the components, advantages, disadvantages, and challenges of redox flow batteries (RFBs). Moreover, it explores various diagnostic techniques employed in analyzing flow batteries. The discussion encompasses the utilization of RFBs for large-scale energy storage applications and summarizes the engineering design aspects related to these batteries. Additionally, this study delves into emerging technologies, applications, and challenges in the realm of redox flow batteries.
... The photovoltaic (PV) modules are directly integrated by stacking with the electrochemical module of RFBs that work autonomously. SRFB technology is in the research and development stage, and it is trying to overcome some of the disadvantages related to its lower capacity, material stability, and insufficient photo voltage [28,[250][251][252][253][254][255][256][257][258][259][260][261][262][263][264][265]. ...
Redox flow batteries represent a captivating class of electrochemical energy systems that are gaining prominence in large-scale storage applications. These batteries offer remarkable scalability, flexible operation, extended cycling life, and moderate maintenance costs. The fundamental operation
and structure of these batteries revolve around the flow of an electrolyte, which facilitates energy conversion and storage. Notably, the power and energy capacities can be independently designed, allowing for the conversion of chemical energy from input fuel into electricity at working electrodes, resembling the functioning of fuel cells. This work provides a comprehensive overview of the components, advantages, disadvantages, and challenges of redox flow batteries (RFBs). Moreover, it explores various diagnostic techniques employed in analyzing flow batteries. The discussion encompasses the utilization of RFBs for large-scale energy storage applications and summarizes the
engineering design aspects related to these batteries. Additionally, this study delves into emerging
technologies, applications, and challenges in the realm of redox flow batteries.
... Similarly, Li et al. 68 used Si-photo electrode along with self-synthesized organic viologen and ferrocene redox couples and achieve solar-to-output electricity efficiency of 5.4% along with an excellent stable cyclic performance for over 200 h and capacitive retention higher than 80%. Further, working on the similar line, Lopez et al. 69 opted for the combination of Si photo-electrodes along with vanadium redox flow batteries. The team fabricated a low-cost integrated PV VRFB with Cu(In, Ga)Se 2 modules of 3 and 4 series-connected cells. ...
The growing demand for alternative renewable sources of energy apart from conventional fossil fuels gathered attention for exploring solar, wind, tidal geothermal energy, etc. However, the intermittent energy supply constraint the full‐fledged utilization of these energy sources and hence, to address this issue, a new technique of integrated energy generation and storage systems (IEGSSs) is extensively explored. In this review, we have comprehensively discussed the ongoing research on various IEGSSs, and their different integration techniques constituting solar cells, batteries, and supercapacitors. This article also highlighted certain challenges faced by the IEGSSs which restrict their full‐fledged application. Finally, some prospects that can flourish their utilization in the field of various portable devices, wearables, off‐grid electrification, and IoT sensors for smart cities are discussed. This article is protected by copyright. All rights reserved.
... It is a promising energy generation and storage technique that is cost-effective and balanced, with the electricity demand way of energy production. The system has been engineered in two architectures [5], (1) where the photoelectrode is integrated directly with RFB and the redox couples of RFB are shared with the photovoltaic cell (PVC) [6][7][8] (Figure 1); and (2) where PVC with an electrochemical module of RFB are stacked together, but each operates autonomously [9][10][11] (Figure 2). Figures 1 and 2 show schematically the structure of SFRBs with photoanodes built on the basis of an n-type semiconductor, which introduces electrons to the working electrode. ...
The dye-sensitized solar cells microfluidically integrated with a redox flow battery (µDSSC-RFB) belong to a new emerging class of green energy sources with an inherent opportunity for energy storage. The successful engineering of microfluidically linked systems is, however, a challenging subject, as the hydrodynamics of electrolyte flow influences the electron and species transport in the system in several ways. In the article, we have analyzed the microflows hydrodynamics by means of the lattice-Boltzmann method, using the algebraic solution of the Navier-Stokes equation for a duct flow and experimentally by the micro particle image velocimetry method. Several prototypes of µDSSC were prepared and tested under different flow conditions. The efficiency of serpentine µDSSC raised from 2.8% for stationary conditions to 3.1% for electrolyte flow above 20 mL/h, while the fill factor increased about 13% and open-circuit voltage from an initial 0.715 V to 0.745 V. Although the hexagonal or circular configurations are the straightforward extensions of standard photo chambers of solar cells, those configurations are hydrodynamically less predictable and unfavorable due to large velocity gradients. The serpentine channel configuration with silver fingers would allow for the scaling of the µDSSC-RFB systems to the industrial scale without loss of performance. Furthermore, the deterioration of cell performance over time can be inhibited by the periodic sensitizer regeneration, which is the inherent advantage of µDSSC.
... [34] Very few works have used carbon substrates with Cl À or seawater-based electrolytes, although it is a highly stable and non-expensive material used in harsh environments and highly developed for flow cell batteries. [35,36] For example, Gupta et al. [37] studied OER electrolysis with bimetallic oxy-boride (CoÀ FeÀ OÀ B) on glassy carbon in 1 m KOH + 0.5 m NaCl, although a 45 % current loss is observed after 20 h. ...
The Cover Feature shows the production of hydrogen by direct seawater splitting on bifunctional (hydrogen and oxygen evolution) graphitic carbon felt electrodes decorated with earth‐abundant NiMoFe catalysts coupled with green renewable energy sources. In addition, the challenges of using real seawater are studied and an electrode regeneration method to face undesired salts deposition is proposed so expensive water purification can be avoided. More information can be found in the Full Paper by C. Ros et al.
... [34] Very few works have used carbon substrates with Cl À or seawater-based electrolytes, although it is a highly stable and non-expensive material used in harsh environments and highly developed for flow cell batteries. [35,36] For example, Gupta et al. [37] studied OER electrolysis with bimetallic oxy-boride (CoÀ FeÀ OÀ B) on glassy carbon in 1 m KOH + 0.5 m NaCl, although a 45 % current loss is observed after 20 h. ...
Hydrogen, produced by water splitting, has been proposed as one of the main green energy vectors of the future if produced from renewable energy sources. However, to substitute fossil fuels, large amounts of pure water are necessary, scarce in many world regions. In this work, we fabricate efficient and earth‐abundant electrodes, study the challenges of using real seawater, and propose an electrode regeneration method to face undesired salt deposition. Ni−Mo−Fe trimetallic electrocatalyst is deposited on non‐expensive graphitic carbon felts both for hydrogen (HER) and oxygen evolution reactions (OER) in seawater and alkaline seawater. Cl⁻ pitting and the chlorine oxidation reaction are suppressed on these substrates and alkalinized electrolyte. Precipitations on the electrodes, mainly CaCO3, originating from seawater‐dissolved components have been studied, and a simple regeneration technique is proposed to rapidly dissolve undesired deposited CaCO3 in acidified seawater. Under alkaline conditions, Ni−Mo−Fe‐based catalyst is found to reconfigure, under cathodic bias, into Ni−Mo−Fe alloy with a cubic crystalline structure and Ni : Fe(OH)2 redeposits whereas, under anodic bias, it is transformed into a follicular Ni:FeOOH structure. High productivities over 300 mA cm⁻² and voltages down to 1.59 V@10 mA cm⁻² for the overall water splitting reaction have been shown, and electrodes are found stable for over 24 h without decay in alkaline seawater conditions and with energy efficiency higher than 61.5 % which makes seawater splitting promising and economically feasible.
... The integration of photoelectron-conversion electrodes into redox flow batteries (so-called Solar redox flow batteries, SRFB) is a promising energy storage technique, offering a cost-effective way for the nextgeneration redox flow batteries (RFB) application in two aspects: i) Operational overpotential of the RFB is greatly reduced for the contribution of the photovoltage; ii) Efficient design, fewer packaging in a compact device for physical size-required applications. The SRFB technology has been developed since 1970 in parallel with RFB ( Fig. 8a) [237][238][239][240][241][242][243][244][245][246][247][248][249][250][251][252]. ...
Redox-flow batteries, based on their particular ability to decouple power and energy, stand as prime candidates
for cost-effective stationary storage, particularly in the case of long discharges and long storage times. Integration
of renewables and subsequent need for energy storage is promoting effort on the development of mature and
emerging redox-flow technologies. This review aims at providing a critical analysis of redox-flow technologies
that can potentially fulfill cost requirements and enable large scale storage, mainly aqueous based systems. A
comprehensive overview of the status of those technologies, including advantages and weaknesses, is presented.
Compiled data on the market permeability, performance and cost should serve, together with the perspective included, to understand the different strategies to reach the successful implementation, from component
development to innovative designs.
... In this kind of RFBs, the same parent molecule is oxidized and reduced on each half-cell. 35,36 Thus, the charge parameters were evaluated by following the same photocharge procedure: initially 10 mL of fresh VO 2+ electrolytes (0.5 M VOSO 4 in 3M H 2 SO 4 ) were added into each compartment (without electrogeneration), after which the PV was illuminated under the same conditions that in the full cell test. This way, the thermodynamic overall cell voltage decreased to around 0.66 V and the photocharge was completed after obtaining V 3+ and VO 2 + in the negative and positive reaction side, respectively. ...
... As proof of concept, the 3CM was first evaluated in a RFB with symmetrical VO 2 + ,VO 2+ ǁ VO 2+ ,V 3+ (V4/V4) configuration, because of the lower standard redox potential between these two vanadium pairs (E 0 = 0.66 V, equation 7). 35 For this purpose, the same starting VO 2+ electrolyte was used in both compartments. The charge profile and the photocurrent density are shown in Figure 3A. ...
