Electroactive Ultra-Thin rGO-Enriched FeMoO4 Nanotubes and MnO2 Nanorods as Electrodes for High-Performance All-Solid-State Asymmetric Supercapacitors

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.

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

Royal Society Open Science ◽

10.1098/rsos.171186 ◽

2018 ◽

Vol 5 (1) ◽

pp. 171186 ◽

Cited By ~ 11

Author(s):

Guofu Ma ◽

Fengting Hua ◽

Kanjun Sun ◽

Enke Fenga ◽

Hui Peng ◽

...

Keyword(s):

Electrode Materials ◽

Rate Capability ◽

Negative Electrode ◽

High Specific Capacitance ◽

High Energy ◽

Cycling Stability ◽

High Energy Density ◽

Storage Device ◽

Asymmetric Supercapacitor ◽

Capacitance Performance

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.

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Stable Lithium-Carbon Composite Enabled by Dual-Salt Additives

Nano-Micro Letters ◽

10.1007/s40820-021-00633-3 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Lei Zheng ◽

Feng Guo ◽

Tuo Kang ◽

Yingzhu Fan ◽

Wei Gu ◽

...

Keyword(s):

Coulombic Efficiency ◽

Solid Electrolyte Interphase ◽

Rate Capability ◽

Negative Electrode ◽

High Energy ◽

Carbon Composite ◽

High Reactivity ◽

Cycling Stability ◽

High Energy Density ◽

Lithium Metal

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.

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Ternary MOF-Based Redox Active Sites Enabled 3D-on-2D Nanoarchitectured Battery-Type Electrodes for High-Energy-Density Supercapatteries

Nano-Micro Letters ◽

10.1007/s40820-020-00528-9 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Goli Nagaraju ◽

S. Chandra Sekhar ◽

Bhimanaboina Ramulu ◽

Sk. Khaja Hussain ◽

D. Narsimulu ◽

...

Keyword(s):

Active Sites ◽

High Performance ◽

Nickel Foam ◽

Rate Capability ◽

Negative Electrode ◽

High Energy ◽

High Energy Density ◽

Phase Method ◽

Charge Storage ◽

Energy Storage Devices

Abstract Designing rationally combined metal–organic frameworks (MOFs) with multifunctional nanogeometries is of significant research interest to enable the electrochemical properties in advanced energy storage devices. Herein, we explored a new class of binder-free dual-layered Ni–Co–Mn-based MOFs (NCM-based MOFs) with three-dimensional (3D)-on-2D nanoarchitectures through a polarity-induced solution-phase method for high-performance supercapatteries. The hierarchical NCM-based MOFs having grown on nickel foam exhibit a battery-type charge storage mechanism with superior areal capacity (1311.4 μAh cm−2 at 5 mA cm−2), good rate capability (61.8%; 811.67 μAh cm−2 at 50 mA cm−2), and an excellent cycling durability. The superior charge storage properties are ascribed to the synergistic features, higher accessible active sites of dual-layered nanogeometries, and exalted redox chemistry of multi metallic guest species, respectively. The bilayered NCM-based MOFs are further employed as a battery-type electrode for the fabrication of supercapattery paradigm with biomass-derived nitrogen/oxygen doped porous carbon as a negative electrode, which demonstrates excellent capacity of 1.6 mAh cm−2 along with high energy and power densities of 1.21 mWh cm−2 and 32.49 mW cm−2, respectively. Following, the MOF-based supercapattery was further assembled with a renewable solar power harvester to use as a self-charging station for various portable electronic applications.

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Ultrathin and porous NiCo2O4 nanosheets based 3D hierarchical electrode materials for high-performance asymmetric supercapacitor

Journal of Electrochemical Energy Conversion and Storage ◽

10.1115/1.4050797 ◽

2021 ◽

pp. 1-11

Author(s):

Fuyong Ren ◽

Zhixiang Tong ◽

Shufen Tan ◽

Junnan Yao ◽

Lijun Pei ◽

...

Keyword(s):

Energy Storage ◽

Active Sites ◽

High Performance ◽

Electrode Materials ◽

Negative Electrode ◽

Cost Effective ◽

High Energy ◽

Porous Nanosheets ◽

High Area ◽

Nico2o4 Nanosheets

Abstract It is well-known that designing unique morphology and structure of electrode materials is an effective strategy to achieve high performance supercapacitors. Herein, the ultrathin and porous NiCo2O4 nanosheets based 3D hierarchical electrode materials were synthesized via a simple and cost effective solvothermal method and subsequent annealing prosses. Since the ultrathin and porous nanosheets could accelerate the transmission of ions and provide numerous active sites, the obtained NiCo2O4 nanosheets based electrode exhibited excellent electrochemical performance with a high area capacity of 5.38 F cm−2 (2690 F g−1) at a current density of 10 mA cm−2 and a good rate performance of 41% capacitance retention at 50 mA cm−2. Furthermore, the corresponding asymmetry supercapacitor was assembled by using the resulted NiCo2O4 nanosheets and active carbon as positive electrode and negative electrode respectively. As expected, the corresponding supercapacitor delivered superior energy density of 52.6 Wh kg−1 at power density of 1.1 kW kg−1 and an extraordinary capacitive retention of 80.9% after 3,000 cycles at 20 mA cm−2. The high energy storage performances suggested that the obtained ultrathin and porous NiCo2O4 nanosheets based 3D hierarchical electrode materials could be prospective candidate in the field of energy storage.

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New Limits for Stability of Supercapacitor Electrode Material Based on Graphene Derivative

Nanomaterials ◽

10.3390/nano10091731 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1731

Author(s):

Veronika Šedajová ◽

Petr Jakubec ◽

Aristides Bakandritsos ◽

Václav Ranc ◽

Michal Otyepka

Keyword(s):

Large Scale ◽

Electrode Materials ◽

High Current Density ◽

Rate Capability ◽

Cycling Stability ◽

Supercapacitor Electrode ◽

Promising Alternative ◽

Practical Applications ◽

High Durability ◽

Graphene Derivatives

Supercapacitors offer a promising alternative to batteries, especially due to their excellent power density and fast charging rate capability. However, the cycling stability and material synthesis reproducibility need to be significantly improved to enhance the reliability and durability of supercapacitors in practical applications. Graphene acid (GA) is a conductive graphene derivative dispersible in water that can be prepared on a large scale from fluorographene. Here, we report a synthesis protocol with high reproducibility for preparing GA. The charging/discharging rate stability and cycling stability of GA were tested in a two-electrode cell with a sulfuric acid electrolyte. The rate stability test revealed that GA could be repeatedly measured at current densities ranging from 1 to 20 A g−1 without any capacitance loss. The cycling stability experiment showed that even after 60,000 cycles, the material kept 95.3% of its specific capacitance at a high current density of 3 A g−1. The findings suggested that covalent graphene derivatives are lightweight electrode materials suitable for developing supercapacitors with extremely high durability.

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Oxygen-Deficient β-MnO2@Graphene Oxide Cathode for High-Rate and Long-Life Aqueous Zinc Ion Batteries

Nano-Micro Letters ◽

10.1007/s40820-021-00691-7 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Shouxiang Ding ◽

Mingzheng Zhang ◽

Runzhi Qin ◽

Jianjun Fang ◽

Hengyu Ren ◽

...

Keyword(s):

Graphene Oxide ◽

Manganese Oxides ◽

Rate Capability ◽

High Energy ◽

Zinc Ion ◽

Cycling Stability ◽

High Rate ◽

High Energy Density ◽

Superior Performance ◽

Long Life

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.

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Hierarchical coral-like MnCo2O4.5@Co-Ni LDH composites on Ni foam as promising electrodes for high-performance supercapacitor

Nanotechnology ◽

10.1088/1361-6528/ac3a3c ◽

2021 ◽

Author(s):

yajun JI ◽

Fei Chen ◽

Shufen Tan ◽

Fuyong Ren

Keyword(s):

Electrochemical Performance ◽

Metal Oxides ◽

High Performance ◽

High Capacity ◽

Rate Capability ◽

Negative Electrode ◽

High Energy ◽

Hybrid Nanostructures ◽

High Energy Density ◽

Ni Foam

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.

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Nano-dendrite structured cobalt phosphide based hybrid supercapacitor with high energy storage and cycling stability

Nanotechnology ◽

10.1088/1361-6528/ac39c8 ◽

2021 ◽

Author(s):

Xiaoyu Chen ◽

Pu Chang ◽

Shuo Zhang ◽

Lixiu Guan ◽

Guohe Ren ◽

...

Keyword(s):

Energy Storage ◽

Specific Capacity ◽

High Energy ◽

Cycling Stability ◽

Activation Process ◽

Carbon Cloth ◽

Cobalt Phosphide ◽

Improved Performance ◽

Transition Metal Phosphides ◽

High Energy Storage

Abstract The supercapacitors possessing high energy storage and long serving period have strategic significance to solve the energy crisis issues. Herein, fluffy nano-dendrite structured cobalt phosphide (CoP) is grown on carbon cloth through simple hydrothermal and electrodeposition treatments (CoP/C-HE). Benefit from its excellent electrical conductivity and special structure, CoP/C-HE manifests a high specific capacity of 461.4 C g-1 at 1 A g-1. Meanwhile, the capacity retention remains 92.8% over 10000 cycles at 5 A g-1, proving the superior cycling stability. The phase conversion of Co2P during the activation process also contributes to the improved performance. The assembled two-electrode asymmetric supercapacitor demonstrates excellent performance in terms of energy density (42.4 W h kg-1 at a power density of 800.0 W kg-1) and cycling stability (86.3% retention over 5000 cycles at 5 A g-1), which is superior to many reported cobalt-based supercapacitors. Our work promotes the potential of transition metal phosphides for the applications in supercapacitors.

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Oxygen-vacancy Bi2O3 nanosheet arrays with excellent rate capability and CoNi2S4 nanoparticles immobilized on N-doped graphene nanotubes as robust electrode materials for high-energy asymmetric supercapacitors

Journal of Materials Chemistry A ◽

10.1039/c8ta11953h ◽

2019 ◽

Vol 7 (13) ◽

pp. 7918-7931 ◽

Cited By ~ 36

Author(s):

Jian Zhao ◽

Zhenjiang Li ◽

Tong Shen ◽

Xiangcheng Yuan ◽

Guanhao Qiu ◽

...

Keyword(s):

Oxygen Vacancy ◽

Electrode Materials ◽

Rate Capability ◽

High Energy ◽

Asymmetric Supercapacitor ◽

Asymmetric Supercapacitors ◽

Positive Electrodes ◽

Nanosheet Arrays ◽

Doped Graphene

An asymmetric supercapacitor with high energy was assembled by using the N-GNTs@OV-Bi2O3 NSAs and N-GNTs@CoNi2S4 NPs as negative and positive electrodes, respectively.

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