scholarly journals Highly Stable Low Redox Potential Quinone for Aqueous Flow Batteries

2021 ◽  
Author(s):  
Min Wu ◽  
Meisam Bahari ◽  
Yan Jing ◽  
Kiana Amini ◽  
Eric Fell ◽  
...  
Keyword(s):  
Redox Potential ◽  
Large Scale ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Single Step ◽  
Capacity Fade ◽  
Formation Reaction ◽  
Performance Improvements ◽  
Flow Batteries ◽  
Aqueous Flow

Aqueous organic redox flow batteries are promising candidates for large-scale energy storage. However, the design of stable and inexpensive electrolytes is challenging. Here, we report a highly stable, low redox potential, and potentially inexpensive negolyte species, sodium 3,3',3'',3'''-((9,10-anthraquinone-2,6-diyl)bis(azanetriyl))tetrakis(propane-1-sulfonate) (2,6-N-TSAQ), which is synthesized in a single step from inexpensive precursors. Pairing 2,6-N-TSAQ with potassium ferrocyanide at pH 14 yielded a battery with the highest open-circuit voltage, 1.14 V, of any anthraquinone-based cell with a capacity fade rate <10%/yr. When 2,6-N-TSAQ was cycled at neutral pH, it exhibited two orders of magnitude higher capacity fade rate. The great difference in anthraquinone cycling stability at different pH is interpreted in terms of the thermodynamics of the anthrone formation reaction. This work shows the great potential of organic synthetic chemistry for the development of viable flow battery electrolytes and demonstrates the remarkable performance improvements achievable with an understanding of decomposition mechanisms.

scholarly journals Efficient CdTe Nanocrystal/TiO2 Hetero-Junction Solar Cells with Open Circuit Voltage Breaking 0.8 V by Incorporating A Thin Layer of CdS Nanocrystal

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 614 ◽  
Author(s):  
Xianglin Mei ◽  
Bin Wu ◽  
Xiuzhen Guo ◽  
Xiaolin Liu ◽  
Zhitao Rong ◽  
...  
Keyword(s):  
Solar Cells ◽  
Thin Layer ◽  
Large Scale ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Band Alignment ◽  
Ambient Conditions ◽  
Solution Processed ◽  
Processing Technologies ◽  
Cdte Nanocrystal

Nanocrystal solar cells (NCs) allow for large scale solution processing under ambient conditions, permitting a promising approach for low-cost photovoltaic products. Although an up to 10% power conversion efficiency (PCE) has been realized with the development of device fabrication technologies, the open circuit voltage (Voc) of CdTe NC solar cells has stagnated below 0.7 V, which is significantly lower than most CdTe thin film solar cells fabricated by vacuum technology (around 0.8 V~0.9 V). To further improve the NC solar cells’ performance, an enhancement in the Voc towards 0.8–1.0 V is urgently required. Given the unique processing technologies and physical properties in CdTe NC, the design of an optimized band alignment and improved junction quality are important issues to obtain efficient solar cells coupled with high Voc. In this work, an efficient method was developed to improve the performance and Voc of solution-processed CdTe nanocrystal/TiO2 hetero-junction solar cells. A thin layer of solution-processed CdS NC film (~5 nm) as introduced into CdTe NC/TiO2 to construct hetero-junction solar cells with an optimized band alignment and p-n junction quality, which resulted in a low dark current density and reduced carrier recombination. As a result, devices with improved performance (5.16% compared to 2.63% for the control device) and a Voc as high as 0.83 V were obtained; this Voc value is a record for a solution-processed CdTe NC solar cell.

Protocrystalline Si:H p-type Layers for Maximization of the Open Circuit Voltage in a-Si:H n-i-p Solar Cells

2002 ◽  
Vol 715 ◽  
Author(s):  
R. J. Koval ◽  
Chi Chen ◽  
G. M. Ferreira ◽  
A. S. Ferlauto ◽  
J. M. Pearce ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Gas Flow ◽  
Open Circuit Voltage ◽  
Film Growth ◽  
Chemical Vapor ◽  
Open Circuit ◽  
Single Step ◽  
Rf Plasma ◽  
Growth Regime

AbstractWe have revisited the issue of p-layer optimization for amorphous silicon (a-Si:H) solar cells, correlating spectroscopic ellipsometry (SE) measurements of the p-layer in the device configuration with light current-voltage (J-V) characteristics of the completed solar cell. Working with p-layer gas mixtures of H2/SiH4/BF3 in rf plasma-enhanced chemical vapor deposition (PECVD), we have found that the maximum open circuit voltage (Voc) for n-i-p solar cells is obtained using p-layers prepared with the maximum possible hydrogen-dilution gas-flow ratio R=[H2]/[SiH4], but without crossing the thickness-dependent transition from the a-Si:H growth regime into the mixed-phase amorphous + microcrystalline [(a+μc)-Si:H] regime for the ∼200 Å p-layers. As a result, optimum single-step p-layers are obtained under conditions similar to those applied for optimum i-layers, i.e., by operating in the so-called “protocrystalline” Si:H film growth regime. The remarkable dependence of the p-layer phase (amorphous vs. microcrystalline) and n-i-p solar cell Voc on the nature of the underlying i-layer surface also supports this conclusion.

Elucidating instabilities contributing to capacity fade in bipyridine‐based materials for non‐aqueous flow batteries

2021 ◽  
Author(s):  
Claudina Kolesnichenko ◽  
Harry Pratt ◽  
Leo J Small ◽  
Travis Mark Anderson
Keyword(s):  
Capacity Fade ◽  
Flow Batteries ◽  
Aqueous Flow

Preparation and Battery Applications of Micron Sized Li4Ti5O2

1997 ◽  
Vol 496 ◽  
Author(s):  
D. Peramunage ◽  
K. M. Abraham
Keyword(s):  
Open Circuit Voltage ◽  
Low Voltage ◽  
Discharge Rate ◽  
Discharge Voltage ◽  
Open Circuit ◽  
Solid Polymer ◽  
Capacity Fade ◽  
Li Battery ◽  
Spinel Cathode ◽  
Small Capacity

ABSTRACTThe objective of this study was to highlight the usefulness of micron-sized Li4Ti5O12 in three distinctive areas: a) cathode of a low-voltage Li battery, b) insertion type auxiliary electrode to investigate the electrochemistry of oxide cathode materials, and c) anode of a Li-ion cell in conjunction with LiMn2O4 cubic spinel cathode. Li cells with Li4Ti5O12 exhibited an open circuit voltage of ∼1.6V, >90% utilization (in terms of the theoretical capacity) at ∼C/10 rate, ∼40% utilization 5C rate, and extended full-depth charge/discharge cycling at ≥ 1C rates with virtually no capacity fade. LiMn2O4 cathodes, evaluated in Li(4+xTi5O12 (x = ∼1.2)/LiMn2O4 cells, exhibited extended full-depth cycling capability with a small capacity fade rate of <0.1% which appeared to slow down with cycling. At a 1C discharge rate, over 190 cycles were demonstrated corresponding to an end utilization of ∼90 mAh/g or ∼0.6 mole Li per LiMn204. Balanced Li4Ti5O12//solid polymer electrolyte//LiMn2O4 full cells of slightly cathode-limited configuration had an open-circuit voltage of ∼3.0V and a mid-discharge voltage of ∼2.5V showing full-depth extended cycling capability at a utilization of ∼90 mAh/g or ∼0.6 mole Li per LiMn204 at the 1C and ∼0.45 mole Li per LiMn2O4 at the 7.5C discharge rate.

scholarly journals Thermodynamically Rigorous Description of the Open Circuit Voltage of Redox Flow Batteries

2021 ◽  
Author(s):  
Nicolas Hayer ◽  
Maximilian Kohns
Keyword(s):  
Activity Coefficients ◽  
Open Circuit Voltage ◽  
Renewable Energy Sources ◽  
Measurement Data ◽  
Open Circuit ◽  
Power Grids ◽  
Nernst Equation ◽  
Rigorous Approach ◽  
Redox Flow Batteries ◽  
Flow Batteries

Redox flow batteries (RFBs) are considered an outstanding candidate for the integration of renewable energy sources into the existing power grids. A key property of RFBs is the open circuit voltage (OCV) corresponding to the currentless equilibrium state. In the literature, the Nernst equation describing this property is often simplified by neglecting the activity coefficients. In this work, using a thermodynamically rigorous approach, we show that activity coefficients have a significant influence on the OCV of the Iron-Cadmium and All-Vanadium RFBs. Moreover, this influence varies with the state of charge. Therefore, activity coefficients should not be neglected in the Nernst equation. We show that when doing so, the resulting offset in OCV is actually comparable to typical voltage losses occurring during operation. Hence, fitting kinetic parameters to measurement data of voltage losses can lead to ambiguous results if only the idealized OCV, obtained by neglecting the activity coefficients, is used in that evaluation. Therefore, the implementation of a thermodynamically rigorous model has the potential to significantly improve state-of-the-art models for RFBs.

Highly Stable Low Redox Potential Quinone for Aqueous Flow Batteries

2022 ◽  
Author(s):  
Min Wu ◽  
Meisam Bahari ◽  
Yan Jing ◽  
Kiana Amini ◽  
Eric M. Fell ◽  
...  
Keyword(s):  
Redox Potential ◽  
Flow Batteries ◽  
Aqueous Flow
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