scholarly journals Synthesis of CNTs/CoNiFe-LDH Nanocomposite with High Specific Surface Area for Asymmetric Supercapacitor

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2155
Author(s):  
Jianwei Wang ◽  
Qian Ding ◽  
Caihui Bai ◽  
Feifei Wang ◽  
Shiguo Sun ◽  
...  

Ternary layered double hydroxide (LDH) materials have shown promising application in hybrid supercapacitors. However, the low electrical conductivity of LDHs is still a restriction to their performance. Herein, carbon nanotubes/cobalt–nickel–iron LDH (CNTs/CoNiFe-LDH) hybrid material was prepared by a one-step hydrothermal approach for the first time. The presence of CNTs improved the conductivity and surface area of the electrode, leading to an enhanced electrochemical performance. The CNTs/CoNiFe-LDH hybrid electrode exhibited high specific capacity 170.6 mAh g−1 at a current density of 1 A g−1, with a capacity retention of 75% at 10 A g−1. CNTs/CoNiFe-LDH//AC asymmetric supercapacitor (ASC) was also assembled, which had high specific capacitance (96.1 F g−1 at the current density of 1 A g−1), good cycling stability (85.0% after 3000 cycles at 15 A g−1) and high energy density (29.9 W h kg−1 at the power density of 750.5 W kg−1). Therefore, the CNTs/CoNiFe-LDH material could be used for hybrid supercapacitor electrodes.

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.


Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1631
Author(s):  
Fangzhou Jin ◽  
Xingxing He ◽  
Jinlong Jiang ◽  
Weijun Zhu ◽  
Jianfeng Dai ◽  
...  

In this work, the hierarchical porous Ni1.5Co1.5S4/g-C3N4 composite was prepared by growing Ni1.5Co1.5S4 nanoparticles on graphitic carbon nitride (g-C3N4) nanosheets via a hydrothermal route. Due to the self-assembly of larger size g-C3N4 nanosheets as a skeleton, the prepared nanocomposite possesses a unique hierarchical porous structure that can provide short ions diffusion and fast electron transport. As a result, the Ni1.5Co1.5S4/g-C3N4 composite exhibits a high specific capacitance of 1827 F g−1 at a current density of 1 A g−1, which is 1.53 times that of pure Ni1.5Co1.5S4 (1191 F g−1). In particular, the Ni1.5Co1.5S4/g-C3N4//activated carbon (AC) asymmetric supercapacitor delivers a high energy density of 49.0 Wh kg−1 at a power density of 799.0 W kg−1. Moreover, the assembled device shows outstanding cycle stability with 95.5% capacitance retention after 8000 cycles at a high current density of 10 A g−1. The attractive performance indicates that the easily synthesized and low-cost Ni1.5Co1.5S4/g-C3N4 composite would be a promising electrode material for supercapacitor application.


Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 893
Author(s):  
TaeGyeong Lim ◽  
TaeYoung Kim ◽  
Ji Won Suk

A porous Cu (P-Cu) mesh was used as a current collector and its morphological effect on the supercapacitor performance was investigated. A porous surface was obtained by thermally annealing the Cu mesh using ammonia gas. Hierarchically porous activated graphene (AG) with a high specific surface area (SSA) was deposited on the P-Cu mesh using electrophoretic deposition, aided by graphene oxide (GO). GO was thermally converted to electrically conductive reduced graphene oxide (rGO). The AG/rGO that was deposited on the P-Cu mesh achieved a high specific capacitance of up to 140.0 F/g and a high energy density of up to 3.11 Wh/kg at a current density of 2 A/g in 6 m KOH aqueous electrolyte. The high SSA of AG and the porous surface morphology of the Cu mesh allowed efficient electric double-layer formation and charge transport. This work offers an alternative to improve supercapacitors by combining a porous metallic current collector with porous AG.


2015 ◽  
Vol 723 ◽  
pp. 789-792
Author(s):  
Ping Huang ◽  
Jia Chun Lu ◽  
Sheng Bo Jiang ◽  
Zhi Chao Liu

Li/graphite fluoride (GFx) cells have been widely noticed during the past decades due to its highest theoretical capacity, high energy density, long shelf life, safety and a wide operating temperature range in primary lithium batteries. Bamboo charcoal is cheap and widely used carbon with high specific surface area and large layer spacing, which is suitable to be fluorinated to form carbon fluoride. Five products with varied fluorine and color were obtained by fluorinating bamboo charcoal under varied reaction conditions. FT-IR spectra of these FBCs were studied. The absorbance peak related to C-F band was involved into five Gaussian peaks, and the area of each peak was calculated. The specific discharge capacity of each product was measured by galvanostatic discharging at 0.01C rate. It is turned out that there is a positive linear relationship between the specific capacity and the percentage of the peak area related to semi-covalent covalent C-F, if the carbon in the products was removed. The discharge curves showed that the discharge process could be divided into three parts. The pure compound corresponding to the first part of the discharge is the target material we actually want.


Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1468 ◽  
Author(s):  
Yun Gu ◽  
Le-Qing Fan ◽  
Jian-Ling Huang ◽  
Cheng-Long Geng ◽  
Jian-Ming Lin ◽  
...  

Co@NiSe2 electrode materials were synthesized via a simple hydrothermal method by using nickel foam in situ as the backbone and subsequently characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and a specific surface area analyzer. Results show that the Co@NiSe2 electrode exhibits a nanowire structure and grows uniformly on the nickel foam base. These features make the electrode show a relatively high specific surface area and electrical conductivity, and thus exhibit excellent electrochemical performance. The obtained electrode has a high specific capacitance of 3167.6 F·g−1 at a current density of 1 A·g−1. To enlarge the potential window and increase the energy density, an asymmetric supercapacitor was assembled by using a Co@NiSe2 electrode and activated carbon acting as positive and negative electrodes, respectively. The prepared asymmetrical supercapacitor functions stably under the potential window of 0–1.6 V. The asymmetric supercapacitor can deliver a high energy density of 50.0 Wh·kg−1 at a power density of 779.0 W·kg−1. Moreover, the prepared asymmetric supercapacitor exhibits a good rate performance and cycle stability.


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.


2021 ◽  
Vol 03 (02) ◽  
pp. 1-1
Author(s):  
Nobuyuki Imanishi ◽  
◽  
Daisuke Mori ◽  
Sou Taminato ◽  
Yasuo Takeda ◽  
...  

Because lithium metal exhibits high specific capacity and low potential, it is the best candidate for fabricating anodes for batteries. Rechargeable batteries fabricated using lithium anode exhibit high capacity and high potential cathode; these can be potentially used to fabricate high energy density batteries (>500 Wh kg–1) that can be used for the development of next-generation electric vehicles. However, the formation and growth of lithium dendrites and the low coulombic efficiency recorded during lithium plating and stripping under conditions of high current density hinder the use of lithium metal as the anodic material for the development of practical rechargeable batteries. In this short review, we outline the current status and prospects of lithium anodes for fabricating batteries in the presence of non-aqueous liquid, polymer, and solid electrolytes operated under conditions of high current density.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4870
Author(s):  
Xiao Li ◽  
Jun Li ◽  
Ying Zhang ◽  
Peng Zhao ◽  
Ruyan Lei ◽  
...  

Ni(OH)2 derived from an MOF template was synthesized as an electrode material for supercapacitors. The electrochemical performance of the electrode was adjusted by effectively regulating the morphology of Ni(OH)2. The evolution of electrochemical performance of the electrode with morphology of Ni(OH)2 was highlighted in detail, based on which honeycomb-like Ni(OH)2 was successfully synthesized, and endowed the electrode with outstanding electrochemical performance. For the three-electrode testing system, honeycomb-like Ni(OH)2 exhibited a very high specific capacitance (1865 F·g−1 at 1 A·g−1, 1550 F·g−1 at 5 mV·s−1). Moreover, it also presented an excellent rate capability and cycling stability, due to 59.46 % of the initial value (1 A·g−1) being retained at 10 A·g−1, and 172% of initial value (first circle at 50 mV·s−1) being retained after 20,000 cycles. With respect to the assembled hybrid supercapacitor, honeycomb-like Ni(OH)2 also displayed superior electrochemical performance, with a high energy density (83.9 Wh·kg−1 at a power density of 374.8 W·kg−1). The outstanding electrochemical performance of Ni(OH)2 should be attributed to its unique honeycomb-like structure, with a very high specific surface area, which greatly accelerates the transformation and diffusion of active ions.


2018 ◽  
Vol 6 (35) ◽  
pp. 17057-17066 ◽  
Author(s):  
Ruiying Shi ◽  
Cuiping Han ◽  
Hongfei Li ◽  
Lei Xu ◽  
Tengfei Zhang ◽  
...  

This work demonstrates egg-white derived activated carbon with exceptionally high specific surface area and improved graphitization degree using NaCl template.


2019 ◽  
Vol 07 (01n02) ◽  
pp. 1950004 ◽  
Author(s):  
Muhammad Sajjad ◽  
Xu Chen ◽  
Chunxin Yu ◽  
Linlin Guan ◽  
Shuyu Zhang ◽  
...  

NiCo2S4/CNTs (NCS/CNTs) hybrid nanostructures have been synthesized by a facile one-step solvothermal method with varying content of CNTs. The structure and morphology of the synthesized NCS/CNTs hybrid revealed the formation of platelets anchored on the CNT matrix. When evaluated as electrode materials for supercapacitor, the as-synthesized NCS/CNT-1 hybrid (with 1% of CNT) manifested remarkable specific capacitance of 1690[Formula: see text]F[Formula: see text]g[Formula: see text] at the current density of 5[Formula: see text]A[Formula: see text]g[Formula: see text]. More importantly, an asymmetric supercapacitor (ASC) assembled based on NCS/CNT-1 as positive electrode and carbon nanotube paper (CNP) as a negative electrode delivered high energy density of 58[Formula: see text]Wh[Formula: see text]kg[Formula: see text] under power density of 8[Formula: see text]kW[Formula: see text]kg[Formula: see text]. Furthermore, the ASC device exhibited high cycling stability and 77.7% of initial specific capacitance retention after 7000 charge–discharge cycles at a current density of 8[Formula: see text]A[Formula: see text]g[Formula: see text]. The large enhancement in the electrochemical performance is attributed to the benefits of the nanostructured architecture, including good mechanical stability, high electrical conductivity as well as buffering for the volume changes during charge–discharge process. These convincing results show that NCS/CNTs hybrid nanostructures are promising electrode materials for high energy density supercapacitors (SCs).


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