scholarly journals Electrochemical Performance and in Operando Charge Efficiency Measurements of Cu/Sn-Doped Nano Iron Electrodes

Batteries ◽  
2018 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
Alagar Paulraj ◽  
Yohannes Kiros ◽  
Mylad Chamoun ◽  
Henrik Svengren ◽  
Dag Noréus ◽  
...  

Fe-air or Ni-Fe cells can offer low-cost and large-scale sustainable energy storage. At present, they are limited by low coulombic efficiency, low active material use, and poor rate capability. To overcome these challenges, two types of nanostructured doped iron materials were investigated: (1) copper and tin doped iron (CuSn); and (2) tin doped iron (Sn). Single-wall carbon nanotube (SWCNT) was added to the electrode and LiOH to the electrolyte. In the 2 wt. % Cu + 2 wt. % Sn sample, the addition of SWCNT increased the discharge capacity from 430 to 475 mAh g−1, and charge efficiency increased from 83% to 93.5%. With the addition of both SWCNT and LiOH, the charge efficiency and discharge capacity improved to 91% and 603 mAh g−1, respectively. Meanwhile, the 4 wt. % Sn substituted sample performance is not on par with the 2 wt. % Cu + 2 wt. % Sn sample. The dopant elements (Cu and Sn) and additives (SWCNT and LiOH) have a major impact on the electrode performance. To understand the relation between hydrogen evolution and charge current density, we have used in operando charging measurements combined with mass spectrometry to quantify the evolved hydrogen. The electrodes that were subjected to prolonged overcharge upon hydrogen evolution failed rapidly. This insight could help in the development of better charging schemes for the iron electrodes.

2020 ◽  
Author(s):  
Mickaël Mateos ◽  
Kenneth D. Harris ◽  
Benoit Limoges ◽  
Véronique Balland

On account of their low-cost, earth abundance, eco-sustainability, and high theoretical charge storage capacity, MnO<sub>2</sub> cathodes have attracted a renewed interest in the development of rechargeable aqueous batteries. However, they currently suffer from limited gravimetric capacities when operating under the preferred mild aqueous conditions, which leads to lower performance as compared to similar devices operating in strongly acidic or basic conditions. Here, we demonstrate how to overcome this limitation by combining a well-defined 3D nanostructured conductive electrode, which ensures an efficient reversible MnO<sub>2</sub>-to-Mn<sup>2+</sup> conversion reaction, with a mild acid buffered electrolyte (pH 5). A reversible gravimetric capacity of 560 mA·h·g<sup>-1</sup> (close to the maximal theoretical capacity of 574 mA·h·g<sup>-1</sup> estimated from the MnO<sub>2</sub> average oxidation state of 3.86) was obtained over rates ranging from 1 to 10 A·g<sup>-1</sup>. The rate capability was also remarkable, demonstrating a capacity retention of 435 mA·h·g<sup>-1</sup> at a rate of 110 A·g<sup>-1</sup>. These good performances have been attributed to optimal regulation of the mass transport and electronic transfer between the three process actors, <i>i.e.</i> the 3D conductive scaffold, the MnO<sub>2</sub> active material filling it, and the soluble species involved in the reversible conversion reaction. Additionally, the high reversibility and cycling stability of this conversion reaction is demonstrated over 900 cycles with a Coulombic efficiency > 99.4 % at a rate of 44 A·g<sup>-1</sup>. Besides these good performances, also demonstrated in a Zn/MnO<sub>2</sub> cell configuration, we discuss the key parameters governing the efficiency of the MnO<sub>2</sub>-to-Mn<sup>2+</sup> conversion. Overall, the present study provides a comprehensive framework for the rational design and optimization of MnO<sub>2</sub> cathodes involved in rechargeable mild aqueous batteries.


2020 ◽  
Author(s):  
Mickaël Mateos ◽  
Kenneth D. Harris ◽  
Benoit Limoges ◽  
Véronique Balland

On account of their low-cost, earth abundance, eco-sustainability, and high theoretical charge storage capacity, MnO<sub>2</sub> cathodes have attracted a renewed interest in the development of rechargeable aqueous batteries. However, they currently suffer from limited gravimetric capacities when operating under the preferred mild aqueous conditions, which leads to lower performance as compared to similar devices operating in strongly acidic or basic conditions. Here, we demonstrate how to overcome this limitation by combining a well-defined 3D nanostructured conductive electrode, which ensures an efficient reversible MnO<sub>2</sub>-to-Mn<sup>2+</sup> conversion reaction, with a mild acid buffered electrolyte (pH 5). A reversible gravimetric capacity of 560 mA·h·g<sup>-1</sup> (close to the maximal theoretical capacity of 574 mA·h·g<sup>-1</sup> estimated from the MnO<sub>2</sub> average oxidation state of 3.86) was obtained over rates ranging from 1 to 10 A·g<sup>-1</sup>. The rate capability was also remarkable, demonstrating a capacity retention of 435 mA·h·g<sup>-1</sup> at a rate of 110 A·g<sup>-1</sup>. These good performances have been attributed to optimal regulation of the mass transport and electronic transfer between the three process actors, <i>i.e.</i> the 3D conductive scaffold, the MnO<sub>2</sub> active material filling it, and the soluble species involved in the reversible conversion reaction. Additionally, the high reversibility and cycling stability of this conversion reaction is demonstrated over 900 cycles with a Coulombic efficiency > 99.4 % at a rate of 44 A·g<sup>-1</sup>. Besides these good performances, also demonstrated in a Zn/MnO<sub>2</sub> cell configuration, we discuss the key parameters governing the efficiency of the MnO<sub>2</sub>-to-Mn<sup>2+</sup> conversion. Overall, the present study provides a comprehensive framework for the rational design and optimization of MnO<sub>2</sub> cathodes involved in rechargeable mild aqueous batteries.


2015 ◽  
Vol 1 (1) ◽  
Author(s):  
A. Sundar Rajan ◽  
M. K. Ravikumar ◽  
K. R. Priolkar ◽  
S. Sampath ◽  
A. K. Shukla

AbstractNickel-iron and iron-air batteries are attractive for large-scale-electrical-energy storage because iron is abundant, low-cost and non-toxic. However, these batteries suffer from poor charge acceptance due to hydrogen evolution during charging. In this study, we have demonstrated iron electrodes prepared from carbonyl iron powder (CIP) that are capable of delivering a specific discharge capacity of about 400 mAh g−1 at a current density of 100 mA g−1 with a faradaic efficiency of about 80%. The specific capacity of the electrodes increases gradually during formation cycles and reaches a maximum in the 180th cycle. The slow increase in the specific capacity is attributed to the low surface area and limited porosity of the pristine CIP. Evolution of charge potential profiles is investigated to understand the extent of charge acceptance during formation cycles. In situ XRD pattern for the electrodes subsequent to 300 charge/discharge cycles confirms the presence of Fe with Fe(OH)2 as dominant phase.


2021 ◽  
Author(s):  
Xianzhong Yang ◽  
Chao Li ◽  
Zhongti Sun ◽  
Shuai Yang ◽  
Zixiong Shi ◽  
...  

Abstract Zn metal anode has garnered growing scientific and industrial interest owing to its appropriate redox potential, low cost and good safety. Nevertheless, the instability of Zn metal, caused by dendrite formation, hydrogen evolution and side reactions, gives rise to poor electrochemical stability and unsatisfactory cycling life, greatly hampering large-scale utilization. Herein, an in-situ grown ZnSe layer with controllable thickness is crafted over one side of commercial Zn foil via chemical vapor deposition, aiming to achieve optimized interfacial manipulation between aqueous electrolyte/Zn anode. Thus-derived ZnSe overlayer not only prevents water penetration and restricts Zn2+ two-dimensional diffusion, but also homogenizes the electric field at the interface and facilitates favorable (002) plane growth of Zn. As a result, dendrite-free and homogeneous Zn deposition is obtained; side reactions are concurrently inhibited. In consequence, a high Coulombic efficiency of 99.2% and high cyclic stability for 860 cycles at 1.0 mA cm–2 in symmetrical cells is harvested. Meanwhile, when paired with V2O5 cathode, assembled full cell achieves an outstanding initial capacity (200 mAh g–1) and elongated lifespan (a capacity retention of 84% after 1000 cycles) at 5.0 A g–1. Our highly reversible Zn anode enabled by the interfacial manipulation strategy is anticipated to satisfy the demand of industrial and commercial use.


NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050062
Author(s):  
Zhaolei Meng ◽  
Xiaojian He ◽  
Song Han ◽  
Zijian Hu

Carbon materials are generally employed as supercapacitor electrodes due to their low- cost, high-chemical stability and environmental friendliness. However, the design of carbon structures with large surface area and controllable porous structure remains a daunt challenge. In this work, a three-dimensional (3D) hybrid aerogel with different contents of MoS2 nanosheets in 3D graphene aerogel (MoS2-GA) was synthesized through a facial hydrothermal process. The influences of MoS2 content on microstructure and subsequently on electrochemical properties of MoS2-GA are systematically investigated and an optimized mass ratio with MoS2: GA of 1:2 is chosen to achieve high mechanical robustness and outstanding electrochemical performance in the hybrid structure. Due to the large specific surface area, porous structure and continuous charge transfer network, such MoS2-GA electrodes exhibit high specific capacitance, good rate capability and excellent cyclic stability, showing great potential in large-scale and low-cost fabrication of high-performance supercapacitors.


2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
He Wang ◽  
Mingning Chang ◽  
Yonglei Zheng ◽  
Ningning Li ◽  
Siheng Chen ◽  
...  

A lithium-rich manganese-based cathode material, Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2, was prepared using a polyvinyl alcohol (PVA)-auxiliary sol-gel process using MnO2 as a template. The effect of the PVA content (0.0–15.0 wt%) on the electrochemical properties and morphology of Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 was investigated. Analysis of Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 X-ray diffraction patterns by RIETAN-FP program confirmed the layered α-NaFeO2 structure. The discharge capacity and coulombic efficiency of Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 in the first cycle were improved with increasing PVA content. In particular, the best material reached a first discharge capacity of 206.0 mAhg−1 and best rate capability (74.8 mAhg−1 at 5 C). Meanwhile, the highest capacity retention was 87.7% for 50 cycles. Finally, electrochemical impedance spectroscopy shows that as the PVA content increases, the charge-transfer resistance decreases.


2020 ◽  
Vol 24 (10) ◽  
pp. 1189-1197
Author(s):  
Naresh Duvva ◽  
Suneel Gangada ◽  
Raghu Chitta ◽  
Lingamallu Giribabu

Limited synthetic steps via low-cost starting materials are needed to develop large-scale light-active materials for efficient solar cells. Here, novel bis(4[Formula: see text]-tert-butylbiphenyl-4-yl)aniline (BBA) based A3B zinc porphyrin (GB) is synthesized and applied as a light harvesting/electron injection material in dye-sensitized solar cells. The GB sensitizer was characterized by various spectroscopic techniques and the optimized device shows [Formula: see text] of 10.98 ± 0.37 mA/cm2 and power conversion efficiency (PCE) of 3.34 ± 0.26%. In addition, performance is enhanced up to ∼3.9% by the addition of co-adsorbent 3a,7a-dihydroxy-5b-cholic acid (chenodeoxycholic acid, CDCA) to minimize [Formula: see text]-[Formula: see text] staking of the planar porphyrin macrocycles. These results demonstrate that novel broad-absorbing light-active material (GB) could be used for indoor solar panels.


MRS Advances ◽  
2020 ◽  
Vol 5 (43) ◽  
pp. 2221-2229
Author(s):  
G. Greco ◽  
S. Passerini

AbstractThe most promising candidate as an everyday alternative to lithium-ion batteries (LIBs) are sodium-ion batteries (NIBs). This is not only due to Na abundance, but also because the main principles and cell structure are very similar to LIBs. Due to these benefits, NIBs are expected to be used in applications related to large-scale energy storage systems and other applications not requiring top-performance in terms of volumetric capacity. One important issue that has hindered the large scale application of NIBs is the anode material. Graphite and silicon, which have been widely applied as anodes in NIBs, do not show great performance. Hard carbons look very promising in terms of their abundance and low cost, but they tend to suffer from instability, in particular over the long term. In this work we explore a carbon-coated TiO2 nanoparticle system that looks very promising in terms of stability, abundance, low-cost, and most importantly that safety of the cell, since it does not suffer from potential sodium plating during cycling. Maintaining a nano-size and consistent morphology of the active material is a crucial parameter for maintaining a well-functioning cell upon cycling. In this work we applied Anomalous Small Angle X-Ray Scattering (ASAXS) for the first time at the Ti K-edge of TiO2 anatase nanoparticles on different cycled composite electrodes in order to have a complete morphological overview of the modifications induced by sodiation and desodiation. This work also demonstrates for the first time that the nanosize of the TiO2 is maintained upon cycling, which is in agreement with the electrochemical stability.


2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Mingguang Wu ◽  
Wei Ni ◽  
Jin Hu ◽  
Jianmin Ma

Abstract Several emerging energy storage technologies and systems have been demonstrated that feature low cost, high rate capability, and durability for potential use in large-scale grid and high-power applications. Owing to its outstanding ion conductivity, ultrafast Na-ion insertion kinetics, excellent structural stability, and large theoretical capacity, the sodium superionic conductor (NASICON)-structured insertion material NaTi2(PO4)3 (NTP) has attracted considerable attention as the optimal electrode material for sodium-ion batteries (SIBs) and Na-ion hybrid capacitors (NHCs). On the basis of recent studies, NaTi2(PO4)3 has raised the rate capabilities, cycling stability, and mass loading of rechargeable SIBs and NHCs to commercially acceptable levels. In this comprehensive review, starting with the structures and electrochemical properties of NTP, we present recent progress in the application of NTP to SIBs, including non-aqueous batteries, aqueous batteries, aqueous batteries with desalination, and sodium-ion hybrid capacitors. After a thorough discussion of the unique NASICON structure of NTP, various strategies for improving the performance of NTP electrode have been presented and summarized in detail. Further, the major challenges and perspectives regarding the prospects for the use of NTP-based electrodes in energy storage systems have also been summarized to offer a guideline for further improving the performance of NTP-based electrodes.


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4565
Author(s):  
Sanghyuk Park ◽  
Kwangho Park ◽  
Ji-Seop Shin ◽  
Gyeongbin Ko ◽  
Wooseok Kim ◽  
...  

We firstly introduce Er and Ga co-doped swedenborgite-structured YBaCo4O7+δ (YBC) as a cathode-active material in lithium-ion batteries (LIBs), aiming at converting the phase instability of YBC at high temperatures into a strategic way of enhancing the structural stability of layered cathode-active materials. Our recent publication reported that Y0.8Er0.2BaCo3.2Ga0.8O7+δ (YEBCG) showed excellent phase stability compared to YBC in a fuel cell operating condition. By contrast, the feasibility of the LiCoO2 (LCO) phase, which is derived from swedenborgite-structured YBC-based materials, as a LIB cathode-active material is investigated and the effects of co-doping with the Er and Ga ions on the structural and electrochemical properties of Li-intercalated YBC are systemically studied. The intrinsic swedenborgite structure of YBC-based materials with tetrahedrally coordinated Co2+/Co3+ are partially transformed into octahedrally coordinated Co3+, resulting in the formation of an LCO layered structure with a space group of R-3m that can work as a Li-ion migration path. Li-intercalated YEBCG (Li[YEBCG]) shows effective suppression of structural phase transition during cycling, leading to the enhancement of LIB performance in Coulombic efficiency, capacity retention, and rate capability. The galvanostatic intermittent titration technique, cyclic voltammetry and electrochemical impedance spectroscopy are performed to elucidate the enhanced phase stability of Li[YEBCG].


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