scholarly journals Nanostructure selenium compounds as pseudocapacitive electrodes for high-performance asymmetric supercapacitor

2018 ◽  
Vol 5 (1) ◽  
pp. 171186 ◽  
Author(s):  
Guofu Ma ◽  
Fengting Hua ◽  
Kanjun Sun ◽  
Enke Fenga ◽  
Hui Peng ◽  
...  

The electrochemical performance of an energy conversion and storage device like the supercapacitor mainly depends on the microstructure and morphology of the electrodes. In this paper, to improve the capacitance performance of the supercapacitor, the all-pseudocapacitive electrodes of lamella-like Bi 18 SeO 29 /BiSe as the negative electrode and flower-like Co 0.85 Se nanosheets as the positive electrode are synthesized by using a facile low-temperature one-step hydrothermal method. The microstructures and morphology of the electrode materials are carefully characterized, and the capacitance performances are also tested. The Bi 18 SeO 29 /BiSe and Co 0.85 Se have high specific capacitance (471.3 F g –1 and 255 F g –1 at 0.5 A g –1 ), high conductivity, outstanding cycling stability, as well as good rate capability. The assembled asymmetric supercapacitor completely based on the pseudocapacitive electrodes exhibits outstanding cycling stability (about 93% capacitance retention after 5000 cycles). Moreover, the devices exhibit high energy density of 24.2 Wh kg –1 at a power density of 871.2 W kg –1 in the voltage window of 0–1.6 V with 2 M KOH solution.

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Lei Zheng ◽  
Feng Guo ◽  
Tuo Kang ◽  
Yingzhu Fan ◽  
Wei Gu ◽  
...  

AbstractLithium metal is regarded as the ultimate negative electrode material for secondary batteries due to its high energy density. However, it suffers from poor cycling stability because of its high reactivity with liquid electrolytes. Therefore, continuous efforts have been put into improving the cycling Coulombic efficiency (CE) to extend the lifespan of the lithium metal negative electrode. Herein, we report that using dual-salt additives of LiPF6 and LiNO3 in an ether solvent-based electrolyte can significantly improve the cycling stability and rate capability of a Li-carbon (Li-CNT) composite. As a result, an average cycling CE as high as 99.30% was obtained for the Li-CNT at a current density of 2.5 mA cm–2 and an negative electrode to positive electrode capacity (N/P) ratio of 2. The cycling stability and rate capability enhancement of the Li-CNT negative electrode could be attributed to the formation of a better solid electrolyte interphase layer that contains both inorganic components and organic polyether. The former component mainly originates from the decomposition of the LiNO3 additive, while the latter comes from the LiPF6-induced ring-opening polymerization of the ether solvent. This novel surface chemistry significantly improves the CE of Li negative electrode, revealing its importance for the practical application of lithium metal batteries.


Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 289 ◽  
Author(s):  
Kugalur Shanmugam Ranjith ◽  
Ganji Seeta Rama Raju ◽  
Nilesh R. Chodankar ◽  
Seyed Majid Ghoreishian ◽  
Cheol Hwan Kwak ◽  
...  

A flexible asymmetric supercapacitor (ASC) with high electrochemical performance was constructed using reduced graphene oxide (rGO)-wrapped redox-active metal oxide-based negative and positive electrodes. Thin layered rGO functionality on the positive and the negative electrode surfaces has promoted the feasible surface-active sites and enhances the electrochemical response with a wide operating voltage window. Herein we report the controlled growth of rGO-wrapped tubular FeMoO4 nanofibers (NFs) via electrospinning followed by surface functionalization as a negative electrode. The tubular structure offers the ultrathin-layer decoration of rGO inside and outside of the tubular walls with uniform wrapping. The rGO-wrapped tubular FeMoO4 NF electrode exhibited a high specific capacitance of 135.2 F g−1 in Na2SO4 neutral electrolyte with an excellent rate capability and cycling stability (96.45% in 5000 cycles) at high current density. Meanwhile, the hydrothermally synthesized binder-free rGO/MnO2 nanorods on carbon cloth (rGO-MnO2@CC) were selected as cathode materials due to their high capacitance and high conductivity. Moreover, the ASC device was fabricated using rGO-wrapped FeMoO4 on carbon cloth (rGO-FeMoO4@CC) as the negative electrode and rGO-MnO2@CC as the positive electrode (rGO-FeMoO4@CC/rGO-MnO2@CC). The rationally designed ASC device delivered an excellent energy density of 38.8 W h kg−1 with a wide operating voltage window of 0.0–1.8 V. The hybrid ASC showed excellent cycling stability of 93.37% capacitance retention for 5000 cycles. Thus, the developed rGO-wrapped FeMoO4 nanotubes and MnO2 nanorods are promising hybrid electrode materials for the development of wide-potential ASCs with high energy and power density.


2020 ◽  
Vol 15 (4) ◽  
pp. 498-503
Author(s):  
Jian Wang ◽  
Yan Zhao ◽  
Dong Zhang ◽  
Yucai Li ◽  
Shiwei Song ◽  
...  

Rational design and construction of hybrid capacitor electrode materials with prominent energy and power density plays an indispensable role for its potential application in energy storage devices. In this work, the nanoflower-like NiCo2O4 samples are successfully prepared on Ni foam via a facile hydrothermal method. The as-fabricated NiCo2O4 samples exhibit superior electrochemical performance with a high specific capacitance of 444.4 F g–1 at 1 A g–1 and excellent capacitance retention. In addition, the as-fabricated device presents a high energy density of 0.298 mWh cm–3 at a power density of 5.71 mW cm–3 and excellent cycle stability with the capacitance retention of 75.6% after 10000 cycles, indicating a promising application as electrodes for energy storage device.


2020 ◽  
Vol 15 (1) ◽  
pp. 147-153
Author(s):  
Yucai Li ◽  
Yan Zhao ◽  
Dong Zhang ◽  
Shiwei Song ◽  
Jian Wang ◽  
...  

Electrochemical performance of the electrode materials is seriously dependent on the structure and morphology of the electrode material. In this work, the nanoflower-like Co3O4 samples are successfully prepared on Ni foam via a facile hydrothermal method. The as-fabricated Co3O4 samples exhibit superior electrochemical performance with a high specific capacitance of 382.6 C g-1 at 1 A g-1 and excellent capacitance retention. In addition, the as-fabricated device presents a high energy density of 23.6 Wh kg-1 at a power density of 508.6 W kg-1 and excellent cycle stability with a capacitance retention of 81.2% after 10000 cycles, indicating a promising application as electrodes for energy storage device.


2018 ◽  
Vol 47 (47) ◽  
pp. 17146-17152 ◽  
Author(s):  
Xiao Liang ◽  
Qiufan Wang ◽  
Yun Ma ◽  
Daohong Zhang

A two-ply CNT yarn asymmetric supercapacitor was fabricated by assembling a CuCo2O4 nanowire positive electrode and a PPy nanoparticle negative electrode. The full cell exhibits a high specific capacitance of 59.55 mF cm−2 and a high energy density of 0.02 mW h cm−2.


2020 ◽  
Vol 10 (8) ◽  
pp. 1308-1316
Author(s):  
Shuang Dong ◽  
Zhengyun Wang ◽  
Junlei Wang ◽  
Yin Yao ◽  
Hongfang Liu

The asymmetric supercapacitor with negative electrode by graphene foam loaded Polypyrrole nanowires (PPy NWs/rGOF) and positive electrode by PPy@MnO2 core–shell nanowires on graphene foam (PPy@MnO2 NWs/rGOF) was developed. The negative electrode was further converted into the positive electrode by one-step redox reaction at room temperature. Graphene foam (rGOF) with unique flexibility, large surface area and high electric conductivity can favor in situ growth of polypyrrole nanowires (PPy NWs) as well as improve cycling stability of the resultant negative electrode. PPy NWs served as the ideal template for the formation of MnO2 shell gives rise to the as-prepared positive electrode with fast electron transport and enhanced active material utilization. Owing to the rational design, the assembled asymmetric supercapacitor was able to be repeatedly discharged/charged at 1.6 V, displaying high energy density of 1.04 mWh cm–3 with improved cycling stability.


RSC Advances ◽  
2015 ◽  
Vol 5 (52) ◽  
pp. 41721-41728 ◽  
Author(s):  
Jia-Jia Li ◽  
Mao-Cheng Liu ◽  
Ling-Bin Kong ◽  
Dan Wang ◽  
Yu-Mei Hu ◽  
...  

Ni3(PO4)2@GO and Fe2O3@GO have been successfully synthesized as electrode materials, and they have been used to assemble an asymmetric supercapacitor (Fe2O3@GO//Ni3(PO4)2@GO), which exhibited a high energy density.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Shouxiang Ding ◽  
Mingzheng Zhang ◽  
Runzhi Qin ◽  
Jianjun Fang ◽  
Hengyu Ren ◽  
...  

AbstractRecent years have witnessed a booming interest in grid-scale electrochemical energy storage, where much attention has been paid to the aqueous zinc ion batteries (AZIBs). Among various cathode materials for AZIBs, manganese oxides have risen to prominence due to their high energy density and low cost. However, sluggish reaction kinetics and poor cycling stability dictate against their practical application. Herein, we demonstrate the combined use of defect engineering and interfacial optimization that can simultaneously promote rate capability and cycling stability of MnO2 cathodes. β-MnO2 with abundant oxygen vacancies (VO) and graphene oxide (GO) wrapping is synthesized, in which VO in the bulk accelerate the charge/discharge kinetics while GO on the surfaces inhibits the Mn dissolution. This electrode shows a sustained reversible capacity of ~ 129.6 mAh g−1 even after 2000 cycles at a current rate of 4C, outperforming the state-of-the-art MnO2-based cathodes. The superior performance can be rationalized by the direct interaction between surface VO and the GO coating layer, as well as the regulation of structural evolution of β-MnO2 during cycling. The combinatorial design scheme in this work offers a practical pathway for obtaining high-rate and long-life cathodes for AZIBs.


2021 ◽  
Author(s):  
yajun JI ◽  
Fei Chen ◽  
Shufen Tan ◽  
Fuyong Ren

Abstract Transition metal oxides are generally designed as hybrid nanostructures with high performance for supercapacitors by enjoying the advantages of various electroactive materials. In this paper, a convenient and efficient route had been proposed to prepare hierarchical coral-like MnCo2O4.5@Co-Ni LDH composites on Ni foam, in which MnCo2O4.5 nanowires were enlaced with ultrathin Co-Ni layered double hydroxides nanosheets to achieve high capacity electrodes for supercapacitors. Due to the synergistic effect of shell Co-Ni LDH and core MnCo2O4.5, the outstanding electrochemical performance in three-electrode configuration was triggered (high area capacitance of 5.08 F/cm2 at 3 mA/cm2 and excellent rate capability of maintaining 61.69 % at 20 mA/cm2), which is superior to those of MnCo2O4.5, Co-Ni LDH and other metal oxides based composites reported. Meanwhile, the as-prepared hierarchical MnCo2O4.5@Co-Ni LDH electrode delivered improved electrical conductivity than that of pristine MnCo2O4.5. Furthermore, the as-constructed asymmetric supercapacitor using MnCo2O4.5@Co-Ni LDH as positive and activated carbon as negative electrode presented a rather high energy density of 220 μWh/cm2 at 2400 μW/cm2 and extraordinary cycling durability with the 100.0 % capacitance retention over 8000 cycles at 20 mA/cm2, demonstrating the best electrochemical performance compared to other asymmetric supercapacitors using metal oxides based composites as positive electrode material. It can be expected that the obtained MnCo2O4.5@Co-Ni LDH could be used as the high performance and cost-effective electrode in supercapacitors.


2021 ◽  
Author(s):  
Yucai Li ◽  
Yan Zhao ◽  
Shiwei Song ◽  
Jian wang

Abstract Core-shell structured NiCo2S4@NiMoO4 is considered to be one of the most promising electrode materials for supercapacitors due to its high specific capacitance and excellent cycle performance. In this work, we report NiCo2S4@NiMoO4 nanosheets on Ni foam by two-step fabricated method. The as-obtained product has high capacitance of 1102.5 F g− 1 at 1 A g− 1. The as-assembled supercapacitor has also a high energy density of 37.6 W h kg− 1 and superior cycle performance with 85% capacitance retention. The electrode materials reported here might exhibits potential applications in future energy storage devices.


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