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1.
Nitrogen doped hierarchical activated carbons with high surface areas and different pore structures are prepared form polyacrylonitrile fibers through KOH activation by two steps. It is found that the specific surface area and porosity of the activated carbons depend strongly on the activation temperatures. The specific surface area increases from 607 m2 g−1 to 3797 m2 g−1 when the activation temperature increases from 600 °C to 800 °C, and then decreases to 3379 m2 g−1 at 900 °C. It shows that the hierarchical activated carbon prepared at a moderate activation temperature of 700 °C exhibits the largest CO2 capture amount, i.e., 5.25 and 3.63 mmol g−1 at 273 and 298 K, respectively, under the pressure of 1 bar. The excellent CO2 capture properties are due to the high specific surface area of 2146 m2 g−1 and high nitrogen content (5.2 wt%) of the obtained sample. On the other hand, when used as supercapacitor electrodes, the sample with the activation temperature at 800 °C shows the largest specific capacitance of 302 F g−1 at a current density of 1 A g−1 in 6 M KOH aqueous electrolyte, with an excellent rate capability of 231 F g−1 at 10 A g−1. Furthermore, a nearly linear relationship between nitrogen content in the nitrogen doped activated carbons and specific CO2 uptake as well as the specific capacitance were first established, indicating nitrogen doping was playing key roles in improving CO2 adsorption and supercapacitor performance. The experimental results indicate that the thus obtained nitrogen doped hierarchical activated carbons are very promising for reducing CO2 green house gas by adsorption as well as storing energy as utilized in supercapacitors.Nitrogen doped activated carbons with high surface area up to 3797 m2 g−1 exhibit specific capacitance of 231 F g−1 at a current density of 10 A g−1. 相似文献
2.
Si Zheng Yin Cui Jianwei Zhang Yuxing Gu Xiaowen Shi Chuang Peng Dihua Wang 《RSC advances》2019,9(19):10976
N-doped porous carbon nanospheres were fabricated directly by pyrolyzing chitin nanogels, which were facilely prepared by mechanical agitation induced sol–gel transition of chitin solution in NaOH/urea solvent. The resulting carbon nanospheres displayed ordered micropores (centered at ∼0.6 nm) and high BET surface area of up to 1363 m2 g−1, which is substantially larger than that of the carbons from raw chitin (600 m2 g−1). In addition, the carbon nanospheres retained a nitrogen content of 3.2% and excellent conductivity. Consequently, supercapacitor electrodes prepared from the carbon nanospheres pyrolyzed at 800 °C showed a specific capacitance as high as 192 F g−1 at a current density of 0.5 A g−1 and impressive rate capability (81% retention at 10 A g−1). When assembled in a symmetrical two-electrode cell, N-doped porous carbon nanospheres demonstrated excellent cycling stability both in aqueous and organic electrolytes (95% retention after 10 000 cycles at 10 A g−1), together with outstanding energy density of 5.1 W h kg−1 at the power density of 2364.9 W kg−1. This work introduces a novel and efficient method to prepared N-doped porous carbon nanospheres directly from chitin and demonstrates the great potential of utilization of abundant polymers from nature in power storage.N-doped microporous carbon nanospheres were directly carbonized from chitin nanogels and demonstrated fascinating supercapacitance performance. 相似文献
3.
Nitrogen doped carbon nanoparticles on highly porous carbon nanofiber electrodes were successfully synthesized via combining centrifugal spinning, chemical polymerization of pyrrole and a two-step heat treatment. Nanoparticle-on-nanofiber morphology with highly porous carbon nanotube like channels were observed from SEM and TEM images. Nitrogen doped carbon nanoparticles on highly porous carbon nanofiber (N-PCNF) electrodes exhibited excellent cycling and C-rate performance with a high reversible capacity of around 280 mA h g−1 in sodium ion batteries. Moreover, at 1000 mA g−1, a high reversible capacity of 172 mA h g−1 was observed after 300 cycles. The superior electrochemical properties were attributed to a highly porous structure with enlarged d-spacings, enriched defects and active sites due to nitrogen doping. The electrochemical results prove that N-PCNF electrodes are promising electrode materials for high performance sodium ion batteries.Nitrogen doped carbon nanoparticles on highly porous carbon nanofiber electrodes were successfully synthesized via combining centrifugal spinning, chemical polymerization of pyrrole and a two-step heat treatment. 相似文献
4.
Xichuan Liu Lei Yuan Minglong Zhong Shuang Ni Fan Yang Zhibing Fu Xibin Xu Chaoyang Wang Yongjian Tang 《RSC advances》2020,10(37):22242
Herein, good electrical conductivity and high specific surface area carbon aerogel (CA) microspheres were synthesized by a facile and economical route using a high temperature carbonization and CO2 activation method. The electroconductive graphitized structure of the CA microspheres could be easily improved by increasing the carbonization temperature. Then the CA microspheres were activated with CO2 to increase the specific surface area of the electrode material for electric double layer capacitors (EDLC). The sample carbonized at 1500 °C for 0.5 h and CO2 activated at 950 °C for 8 h showed an acceptable specific surface area and excellent cycle performance and rate capability for EDLC: 98% of the initial value of the capacitance was retained after 10 000 cycles, a specific capacitance of 121 F g−1 at 0.2 A g−1 and 101 F g−1 at 2 A g−1.Carbon aerogels (CAs) microspheres with good electrical conductivity and high specific surface area were synthesized by high temperature carbonization and CO2 activation method, which exhibit an enhanced capacitive performance in supercapacitors. 相似文献
5.
Sayali B. Kale Manjiri A. Mahadadalkar Chang Hyo Kim Yoong Ahm Kim Manish S. Jayswal Kap Seung Yang Bharat B. Kale 《RSC advances》2019,9(62):36075
Nitrogen enriched carbon nanofibers have been obtained by one-step carbonization/activation of PAN-based nanofibers with various concentrations of melamine at 800 °C under a N2 atmosphere. As synthesised carbon nanofibers were directly used as electrodes for symmetric supercapacitors. The obtained PAN-MEL fibers with 5% melamine stabilised at 280 °C and carbonized at 800 °C under a nitrogen atmosphere showed excellent electrochemical performance with a specific capacitance of up to 166 F g−1 at a current density of 1A g−1 using 6 M KOH electrolyte and a capacity retention of 109.7% after 3000 cycles. It shows a 48% increase as compared to pristine carbon nanofibers. Two electrode systems of the CNFM5 sample showed high energy densities of 23.72 to 12.50 W h kg−1 at power densities from 400 to 30 000 W kg−1. When used as an anode for Li-ion battery application the CNFM5 sample showed a high specific capacity up to 435.47 mA h g−1 at 20 mA g−1, good rate capacity and excellent cycling performance (365 mA h g−1 specific capacity even after 200 cycles at 100 mA g−1). The specific capacity obtained for these nitrogen enriched carbon nanofibers is higher than that for pristine carbon nano-fibers.Nitrogen enriched carbon nanofibers have been obtained by one-step carbonization/activation of PAN-based nanofibers with various concentrations of melamine at 800 °C under a N2 atmosphere. 相似文献
6.
Yingfang Jiang Zhengwei Zhang Yagang Zhang Xin Zhou Lulu Wang Akram Yasin Letao Zhang 《RSC advances》2018,8(74):42405
Biomass-derived porous carbon materials have drawn considerable attention due to their natural abundance and low cost. In this work, nitrogen enriched porous carbons (NRPCs) with large surface areas were designed and prepared from cottonseed hull via simultaneous carbonization and activation with a facile one-pot approach. The NRPCs were tunable in terms of pore structure, nitrogen content and morphology by adjusting the ratio of the carbon precursor (cottonseed hull), nitrogen source (urea), and activation agent (KOH). The as-synthesized NRPCs exhibited three-dimensional oriented and interlinked porous structure, high specific surface area (1160–2573 m2 g−1) and a high level of nitrogen-doping (6.02–10.7%). In a three electrode system, NRPCs prepared at 800 °C with the ratio (cottonseed hull : KOH : urea) of 1 : 1 : 2 (NRPC-112) showed a high specific capacitance of 340 F g−1 at a current density of 0.5 A g−1 and good rate capability (∼80% retention at a current density of 10 A g−1) with 6 M KOH as electrolyte. In a two electrode cell, NRPC-112 demonstrated a high specific capacitance of 304 F g−1 at 0.5 A g−1 and an excellent rate capacity (∼71% retention at current density of 10 A g−1) as well as excellent cycling stability (∼91% retention at 5 A g−1) after 5000 cycles. Furthermore, the NRPCs exhibited an extraordinary adsorption capacity up to 205 mg g−1 for emerging pollutant triclosan. The work provided a sustainable approach to prepare functional carbon materials from biomass-based resource for environment remediation and electrochemical applications.Biomass derived nitrogen-enriched porous carbon materials from cottonseed hull for emerging pollutant triclosan removal and electrochemical application. 相似文献
7.
Long Ren Bin Xu Guodong Wang Xiaoshuang Yin Ying Liu Wenzhong Yang Yun Chen 《RSC advances》2020,10(64):39130
In this study, antimony doped tin oxide loaded reduced graphene oxide (ATO–RGO) nanocomposites were synthesized via a facile hydrothermal approach. As a typical N-type semiconductor, the ATO in the composite can enhance the conductivity between graphene sheets, thus improving the specific capacitance and electrosorption performance. Under the optimal conditions, the largest surface area was 445.2 m2 g−1 when the mass content of ATO in the nanocomposite was 20 wt%. The synthesized optimal ATO–RGO electrode displayed excellent specific capacity (158.2 F g−1) and outstanding electrosorptive capacity (8.63 mg g−1) in sodium chloride solution, which were much higher than the corresponding results of pristine graphene (74.3 F g−1 and 3.98 mg g−1). At the same applied voltage, electrosorption capacity and charge efficiency of the ATO–RGO (20 wt%) material were better than those of reported carbon materials in recent years.Antimony doped tin oxide–graphene nanocomposites synthesized via a facile hydrothermal approach displayed good specific capacity and electrosorptive capacity. 相似文献
8.
The remnants of the anaerobic digestion process, ‘the digestate,’ mainly consist of fibrous lignin and cellulose like molecules, as a significant carbon repository along with some other inorganic impurities. The present work demonstrates the potential use of anaerobically treated fruit and vegetable waste (FVW) as a source of porous carbon for supercapacitor electrode materials. This work suggests that the FVW digestate can inherit silicon (Si) and calcium (Ca) based inorganic impurities, which play an essential role as structure directing agents for digestate derived carbon. These contaminants act as hard templates during carbonization to create hierarchical pores and contribute to an enhancement in surface area. Different batches from an anaerobic biogas digester plant are converted to porous carbon and examined as a potential supercapacitor electrode material. A maximum capacitance of 235 F g−1 is achieved from DDHPC-4kh carbon with a specific surface area of 2502 m2 g−1 at a current density of 1 A g−1 in an acidic aqueous electrolyte. The results are significant in comparison to other bio-sourced precursors studied previously.The remnants of the anaerobic digestion process, ‘the digestate,’ mainly consist of fibrous lignin and cellulose like molecules, as a significant carbon repository along with some other inorganic impurities. 相似文献
9.
Jinglei Xie Hongjie Zhang Shuai An Xuejun Qian Hongshun Cheng Fengshan Zhang Xiaoliang Li 《RSC advances》2018,8(6):3081
The fiber surface wettability is one of the most important lignocellulosic fiber characteristics affecting the inter-fiber bonding properties of final bio-products. In this study, the surface wettability (evaluated by the surface free energy, surface lignin and surface charge) of mechanically refined fibers and the bonding properties of the fiber matrix (handsheets) were measured and correlated to each other. The results showed that the fiber surface charge increased from 48.38 mmol kg−1 to 60.38 mmol kg−1 and the surface lignin decreased from 87.1% to 77.5% during the fiber mechanical treatment, leading to the improvement of the fiber surface free energy from 46.63 mJ m−2 to 54.45 mJ m−2. As a result, the bonding strength index increased from 2.60 N m g−1 to 9.73 N m g−1 without significant loss of bulk properties. In a word, the fiber surface wettability could be adjusted to facilitate the inter-fiber bonding properties of the paper or paperboard products using lignin-rich fibers as raw materials.The fiber surface wettability is one of the most important lignocellulosic fiber characteristics affecting the inter-fiber bonding properties of final bio-products. 相似文献
10.
Qingchao Fan Chang Ma Liqiang Wu Chengbiao Wei Huihui Wang Yan Song Jingli Shi 《RSC advances》2019,9(12):6419
Porous carbon nanofibers are fabricated by one-step carbonization and activation of electrospun cellulose acetate (CA) nanofibres. Electrospun CA nanofibers were obtained by the electrospinning of a CA/DMAC/acetone solution, followed by deacetylation in NaOH/ethanol solution. One-step carbonization and activation was achieved by dipping the as-spun fibers in ZnCl2 solution, followed by one-step high temperature treatment. The effects of the concentration of the dipping solution on the microstructure of the CA-based carbon nanofibers (CACNFs), including the morphology, crystal structure, porous structure, specific surface area and surface chemical properties, have been investigated. The coating of ZnCl2 effectively improves the thermal stability of electrospun CA nanofibers and obviously enhances the oxygen-containing surface groups of the CACNFs. The CACNFs have a norrow pore size distribution (0.6–1.2 nm) and a high specific surface area (∼1188 m2 g−1). Electrochemical performances of the CACNFs were evaluated as supercapacitor electrodes in 6 M KOH solution. The CACNFs demonstrate high specific capacitance (202 F g−1 at 0.1 A g−1) and excellent rate capability (61% of the retention from 0.1 to 20 A g−1). After 5000 cycles of the electrode, the capacitance is maintained at 92%, and the coulombic efficiency is close to 100%, showing high electrochemical stability and reversibility. The renewable features and excellent performance make CACNFs quite a promising alternative to efficient supercapacitor electrodes for energy storage applications.Porous carbon nanofibers are fabricated by one-step carbonization and activation of electrospun cellulose acetate (CA) nanofibres. 相似文献
11.
Nickel cobalt sulfide nanoparticles (NCS) embedded onto a nitrogen and sulfur dual doped graphene (NS-G) surface are successfully synthesized via a two-step facile hydrothermal process. The electrical double-layer capacitor of NS-G acts as a supporting host for the growth of pseudocapacitance NCS nanoparticles, thus enhancing the synergistic electrochemical performance. The specific capacitance values of 1420.2 F g−1 at 10 mV s−1 and 630.6 F g−1 at 1 A g−1 are achieved with an impressive capability rate of 76.6% preservation at 10 A g−1. Furthermore, the integrating NiCo2S4 nanoparticles embedding onto the NS-G surface also present a surprising improvement in the cycle performance, maintaining 110% retention after 10 000 cycles. Owing to the unique morphology an impressive energy density of 19.35 W h kg−1 at a power density of 235.0 W kg−1 suggests its potential application in high-performance supercapacitors.Newly developed in situ hydrothermal synthesis governs morphology of Ni–Co–S embedded on N–S doped graphene thus providing exceptional capacitive behavior. 相似文献
12.
Bing Hu Wei-Bin Zhang Kun Yan Tong Zhang Kai Li Xi-Wen Chen Long Kang Ling-Bin Kong 《RSC advances》2018,8(61):35083
A chemical process was developed to prepare N-doped micro-nano carbon spheres with multi-scale pore structures via carbonization of N-PF/PMMA interpenetrating polymer networks, which contain melamine resin as the nitrogen source, PF as the carbon source, and polymethylmethacrylate (PMMA) as the pore-former. The N-content of N-doped micro-nano carbon spheres was controlled by adjusting the mass ratio of melamine and phenol before polymerization. The N-doped micro-nano carbon spheres as electrode materials possess appropriate pore size distribution, higher specific surface area (559 m2 g−1) and consistently dispersed nitrogen atoms with adjustable doping content. These distinct characteristics endow the prospective electrode materials with excellent performance in electrochemical capacitors. In particular, N-CS-IPN-4 exhibits the highest specific capacitance of 364 F g−1 at 0.5 A g−1 in 6 M KOH aqueous electrolyte in a three-electrode system. It also possesses superior rate capability (57.7% retention at current densities ranging from 0.5 to 50 A g−1) and excellent cycling performance at 2 A g−1 (100% retention after 10 000 cycles). All these results confirm that the N-doped micro-nano carbon spheres are promising electrochemical capacitor materials, which possesses the advantages of simple preparation procedure, multi-scale pore structures, higher specific surface areas, easy adjustment of N-content and excellent electrochemical properties.The N-doped micro-nano carbon spheres with multi-scale pore structures was prepared via carbonization of N-PF/PMMA interpenetrating polymer networks, which contain melamine resin as nitrogen source, PF as carbon source, and PMMA as pore-former. 相似文献
13.
Wenjie Fan Hao Zhang Huanlei Wang Xiaochen Zhao Shijiao Sun Jing Shi Minghua Huang Wei Liu Yulong Zheng Ping Li 《RSC advances》2019,9(56):32382
Nowadays, designing heteroatom-doped porous carbons from inexpensive biomass raw materials is a very attractive topic. Herein, we propose a simple approach to prepare heteroatom-doped porous carbons by using nettle leaves as the precursor and KOH as the activating agent. The nettle leaf derived porous carbons possess high specific surface area (up to 1951 m2 g−1), large total pore volume (up to 1.374 cm3 g−1), and high content of nitrogen and oxygen heteroatom doping (up to 17.85 at% combined). The obtained carbon as an electrode for symmetric supercapacitors with an ionic liquid electrolyte can offer a superior specific capacitance of 163 F g−1 at 0.5 A g−1 with a capacitance retention ratio as high as 67.5% at 100 A g−1, and a low capacitance loss of 8% after 10 000 cycles. Besides, the as-built supercapacitor demonstrates a high specific energy of 50 W h kg−1 at a specific power of 372 W kg−1, and maintains 21 W h kg−1 at the high power of 40 kW kg−1. Moreover, the resultant carbon as a Li-ion battery anode delivers a high reversible capacity of 1262 mA h g−1 at 0.1 A g−1 and 730 mA h g−1 at 0.5 A g−1, and maintains a high capacity of 439 mA h g−1 after 500 cycles at 1 A g−1. These results demonstrate that the nettle leaf derived porous carbons offer great potential as electrodes for advanced supercapacitors and lithium ion batteries.Nettle leaf derived nitrogen and oxygen dual-doped porous carbons exhibit great potential as anodes for high performance supercapacitors and lithium ion batteries. 相似文献
14.
Based on the complexes formed by the original Cr(iii) in chrome-tanned leather shavings and the carboxyl groups in collagen as raw materials, a chromium oxide-carbon composite material was formed by the high-temperature carbonization of chromium-tanned leather shavings, followed by the leaching of chrome oxide and activation by KOH. By this method, the hierarchical porous carbon with a high surface area doped with oxygen and nitrogen was prepared. The forming process of the hierarchical porous structure is discussed in detail. Through adjusting the mass ratio of KOH to carbon during the activation process, with a mass ratio of 2, the chromium-tanned leather shavings-based hierarchical porous carbon (called CTSHPC-2) was prepared with an optimal specific surface area (3211 m2 g−1) and a large volume ratio of mesopores to macropores (61.9%) as well as abundant oxygen (13.92 at%) and nitrogen (3.58 at%) functional groups. The results showed that CTSHPC-2 obtained a high specific capacitance of 335.5 F g−1 at a current density of 0.5 A g−1. In addition, it had higher rate performance, low resistance, and better cycle stability. Even when the current density is 10 A g−1 over 5000 cycles, the specific capacity retention rate is 93.5%. Therefore, CTSHPC-2 is a promising electrode material for supercapacitors.A chromium oxide-carbon composite material was formed by the high-temperature carbonization of chromium-tanned leather shavings, followed by the leaching of chrome oxide and activation by KOH. 相似文献
15.
Hollow ZIF-8 was assembled into fiber to fabricate a nitrogen-doped hierarchical porous CNF electrode, which exhibits specific capacitance of 394 F g−1 at 1 A g−1 and excellent rate performance with a retention of up to 76.1% at 20 A −1, exceeding those of many previously reported 1D carbon materials.Hollow ZIF-8 shells were assembled into fibers to obtain nitrogen-doped hierarchical porous carbon nanofibers for excellent supercapacitor application. 相似文献
16.
Hanwei Wang Chengmin Sheng Tailong Cai Chunde Jin Qingfeng Sun Chao Wang 《RSC advances》2018,8(22):12204
In this study, N-doped mesopore-dominant carbon (NMC) materials were prepared using bio-waste tortoise shells as a carbon source via a one-step self-activation process. With intrinsic hydroxyapatites (HAPs) as natural templates to fulfill the synchronous carbonization and activation of the precursor, this highly efficient and time-saving method provides N-doped carbon materials that represent a large mesopore volume proportion of 74.59%, a high conductivity of 4382 m S−1, as well as larger defects, as demonstrated by Raman and XRD studies. These features make the NMC exhibit a high reversible lithium-storage capacity of 970 mA h g−1 at 0.1 A g−1, a strong rate capability of 818 mA h g−1 at 2 A g−1, and a good capacity of 831 mA h g−1 after 500 cycles at 1 A g−1. This study provides a highly efficient and feasible method to prepare renewable biomass-derived carbons as advanced electrode materials for the application of energy storage.A hydroxyapatite-induced self-activation method has been used to prepare nitrogen-doped mesopore-dominant carbon. The carbon has abundant macro/mesopores, high conductivity, and favorable defects and exhibited high-performance in LIBs. 相似文献
17.
Hua Fang Fanteng Meng Ji Yan Gao-yun Chen Linsen Zhang Shide Wu Shichao Zhang Lizhen Wang Yongxia Zhang 《RSC advances》2019,9(35):20107
Highly wrinkled graphene film (HWGF) with high packing density was synthesized by combining an electrostatically self-assembling process, a vacuum filtration-induced film assembling process and capillary compression. Fe3O4 nanoparticles were used as a low-cost and environment-friendly hard template. Hierarchical porosity and high packing density were achieved with the aid of capillary compression in the presence of Fe3O4 nanoparticles. This strategy enables integration of highly wrinkled graphene sheets to form highly compact carbon electrodes with a continuous ion transport network. The generated HWGF exhibited a high packing density of 1.53 g cm−3, a high specific surface area of 383 m2 g−1 and a hierarchically porous structure. The HWGF delivered a high capacitance of 242 F g−1 and 370 F cm−3 at 0.2 A g−1 in 6 M KOH aqueous electrolyte system with excellent rate capability (202 F g−1 and 309 F cm−3 retained at 20 A g−1). The capacity retention rate reached 97% after 10 000 cycles at 1 A g−1. The HWGF-based supercapacitor exhibited a high energy density of 17 W h kg−1 at the power density of 49 W kg−1. Such high capacitive performances could be attributed to the highly dense but porous graphene assemblies composed of highly wrinkled graphene sheets.A facile strategy was reported to synthesize highly wrinkled graphene film, exhibiting high packing density and excellent capacitive performance. 相似文献
18.
Chao Liu Gaofeng Shi Guoying Wang Puranjan Mishra Shiming Jia Xia Jiang Peng Zhang Yucan Dong Zhao Wang 《RSC advances》2019,9(12):6898
An ultra-facile fabrication process for the preparation of phosphorus doped porous carbon nanofibers (P-PCNFs) through the electrospinning and heat treatment method has been studied. The materials were characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Studies showed that fabricated P-PCNFs have unique porous fibers structures, large specific surface area (462.83 cm2 g−1), and abundant microporous and mesoporous structures. X-ray photoelectron spectroscopy analyses revealed that the contents of phosphorus and electrochemical properties in a series of P-PCNF samples can be tuned by controlling the polyphosphoric acid concentration. The electrochemical properties of the materials were evaluated using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. Studies showed that the specific capacitance of the fabricated P-PCNFs using the ultra-facile process reached up to 228.7 F g−1 at 0.5 A g−1 in 1 M H2SO4. Over 84.37% of the initial capacitance remains as the current density increases from 0.5 to 10 A g−1. Meanwhile, at a current density of 2 A g−1, no capacitance loss was observed in 5000 charge/discharge cycles. The highest voltage windows of sample P-PCNFs-1.0 in 1 M H2SO4 aqueous electrolyte can reach 1.4 V. These properties suggest that the fabricated P-PCNFs exhibit excellent electrochemical properties. Conclusively, the surface of carbon nanofibers can be modified by heteroatom doping or surface activation which can improve the electrochemical performance of the materials.Preparation of phosphorus-doped porous carbon nanofibers, with excellent capacitance properties, by electrospinning, using polyethylene glycol as a pore-making agent and polyphosphoric acid as a phosphorus source. 相似文献
19.
Jinying Wei Daping Qiu Min Li Zhenyu Xie Ang Gao Hongru Liu Suhong Yin Dongsheng Yang Ru Yang 《RSC advances》2019,9(18):10237
Ion substitution and micromorphology control are two efficient strategies to ameliorate the electrochemical performance of supercapacitors electrode materials. Here, Al3+ doped α-Ni(OH)2 with peony-like morphology and porous structure has been successfully synthesized through a facile one-pot hydrothermal process. The Al3+ doped α-Ni(OH)2 electrode shows an ultrahigh specific capacitance of 1750 F g−1 at 1 A g−1, and an outstanding electrochemical stability of 72% after running 2000 cycles. In addition, the Al3+ doped α-Ni(OH)2 electrode demonstrates an excellent rate capability (92% retention at 10 A g−1). Furthermore, by using this unique Al3+ doped α-Ni(OH)2 as the positive electrode and a hierarchical porous carbon (HPC) as the negative electrode, the assembled asymmetric supercapacitor can demonstrate a high energy/power density (49.6 W h kg−1 and 14 kW kg−1). This work proves that synthesizing an Al3+ doped structure is an effective means to improve the electrochemical properties of α-Ni(OH)2. This scheme could be extended to other transition metal hydroxides to enhance their electrochemical performance.Ion substitution and micromorphology control are two efficient strategies to ameliorate the electrochemical performance of supercapacitors electrode materials. 相似文献
20.
Chong Wang Changzhen Zhan Xiaolong Ren Ruitao Lv Wanci Shen Feiyu Kang Zheng-Hong Huang 《RSC advances》2019,9(72):42316
Lithium ion capacitors (LICs), bridging the advantages of batteries and electrochemical capacitors, are regarded as one of the most promising energy storage devices. Nevertheless, it is always limited by the anodes that accompany with low capacity and poor rate performance. Here, we develop a versatile and scalable method including ball-milling and pyrolysis to synthesize exfoliated MoS2 supported by N-doped carbon matrix derived from chitosan, which is encapsulated by pitch-derived carbon shells (MoS2/CP). Because the carbon matrix with high nitrogen content can improve the electron conductivity, the robust carbon shells can suppress the volume expansion during cycles, and the sufficient exfoliation of lamellar MoS2 can reduce the ions transfer paths, the MoS2/CP electrode delivers high specific capacity (530 mA h g−1 at 100 mA g−1), remarkable rate capability (230 mA h g−1 at 10 A g−1) and superior cycle performance (73% retention after 250 cycles). Thereby, the LICs, composed of MoS2/CP as the anode and commercial activated carbon (21 KS) as the cathode, exhibit high power density of 35.81 kW kg−1 at 19.86 W h kg−1 and high energy density of 87.74 W h kg−1 at 0.253 kW kg−1.MoS2/carbon composites prepared by ball-milling and pyrolysis for the high-rate anode of lithium ion capacitors. 相似文献