Research

13 pages, 4232 KiB

Open AccessArticle

Synthesis and Characterization of a NiCo₂O₄@NiCo₂O₄ Hierarchical Mesoporous Nanoflake Electrode for Supercapacitor Applications

by Xin Chen, Hui Li, Jianzhou Xu, F. Jaber, F. Musharavati, Erfan Zalnezhad, S. Bae, K.S. Hui, K.N. Hui and Junxing Liu

Nanomaterials 2020, 10(7), 1292; https://doi.org/10.3390/nano10071292 - 30 Jun 2020

Cited by 36 | Viewed by 5152

Abstract

In this study, we synthesized binder-free NiCo₂O₄@NiCo₂O₄ nanostructured materials on nickel foam (NF) by combined hydrothermal and cyclic voltammetry deposition techniques followed by calcination at 350 °C to attain high-performance supercapacitors. The hierarchical porous NiCo₂ [...] Read more.

In this study, we synthesized binder-free NiCo₂O₄@NiCo₂O₄ nanostructured materials on nickel foam (NF) by combined hydrothermal and cyclic voltammetry deposition techniques followed by calcination at 350 °C to attain high-performance supercapacitors. The hierarchical porous NiCo₂O₄@NiCo₂O₄ structure, facilitating faster mass transport, exhibited good cycling stability of 83.6% after 5000 cycles and outstanding specific capacitance of 1398.73 F g⁻¹ at the current density of 2 A·g⁻¹, signifying its potential for energy storage applications. A solid-state supercapacitor was fabricated with the NiCo₂O₄@NiCo₂O₄ on NF as the positive electrode and the active carbon (AC) was deposited on NF as the negative electrode, delivering a high energy density of 46.46 Wh kg⁻¹ at the power density of 269.77 W kg⁻¹. This outstanding performance was attributed to its layered morphological characteristics. This study explored the potential application of cyclic voltammetry depositions in preparing binder-free NiCo₂O₄@NiCo₂O₄ materials with more uniform architecture for energy storage, in contrast to the traditional galvanostatic deposition methods. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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17 pages, 4947 KiB

Open AccessArticle

Binder Free and Flexible Asymmetric Supercapacitor Exploiting Mn₃O₄ and MoS₂ Nanoflakes on Carbon Fibers

by Amjid Rafique, Usman Zubair, Mara Serrapede, Marco Fontana, Stefano Bianco, Paola Rivolo, Candido F. Pirri and Andrea Lamberti

Nanomaterials 2020, 10(6), 1084; https://doi.org/10.3390/nano10061084 - 31 May 2020

Cited by 30 | Viewed by 4419

Abstract

Emerging technologies, such as portable electronics, have had a huge impact on societal norms, such as access to real time information. To perform these tasks, portable electronic devices need more and more accessories for the processing and dispensation of the data, resulting in [...] Read more.

Emerging technologies, such as portable electronics, have had a huge impact on societal norms, such as access to real time information. To perform these tasks, portable electronic devices need more and more accessories for the processing and dispensation of the data, resulting in higher demand for energy and power. To overcome this problem, a low cost high-performing flexible fiber shaped asymmetric supercapacitor was fabricated, exploiting 3D-spinel manganese oxide Mn₃O₄ as cathode and 2D molybdenum disulfide MoS₂ as anode. These asymmetric supercapacitors with stretched operating voltage window of 1.8 V exhibit high specific capacitance and energy density, good rate capability and cyclic stability after 3000 cycles, with a capacitance retention of more than 80%. This device has also shown an excellent bending stability at different bending conditions. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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11 pages, 2813 KiB

Open AccessArticle

Sn-Doping and Li₂SnO₃ Nano-Coating Layer Co-Modified LiNi_0.5Co_0.2Mn_0.3O₂ with Improved Cycle Stability at 4.6 V Cut-off Voltage

by Huali Zhu, Rui Shen, Yiwei Tang, Xiaoyan Yan, Jun Liu, Liubin Song, Zhiqiang Fan, Shilin Zheng and Zhaoyong Chen

Nanomaterials 2020, 10(5), 868; https://doi.org/10.3390/nano10050868 - 30 Apr 2020

Cited by 32 | Viewed by 2975

Abstract

Nickel-rich layered LiNi_1−x−yCo_xMn_yO₂ (LiMO₂) is widely investigated as a promising cathode material for advanced lithium-ion batteries used in electric vehicles, and a much higher energy density in higher cut-off voltage is [...] Read more.

Nickel-rich layered LiNi_1−x−yCo_xMn_yO₂ (LiMO₂) is widely investigated as a promising cathode material for advanced lithium-ion batteries used in electric vehicles, and a much higher energy density in higher cut-off voltage is emergent for long driving range. However, during extensive cycling when charged to higher voltage, the battery exhibits severe capacity fading and obvious structural collapse, which leads to poor cycle stability. Herein, Sn-doping and in situ formed Li₂SnO₃ nano-coating layer co-modified spherical-like LiNi_0.5Co_0.2Mn_0.3O₂ samples were successfully prepared using a facile molten salt method and demonstrated excellent cyclic properties and high-rate capabilities. The transition metal site was expected to be substituted by Sn in this study. The original crystal structures of the layered materials were influenced by Sn-doping. Sn not only entered into the crystal lattice of LiNi_0.5Co_0.2Mn_0.3O₂, but also formed Li⁺-conductive Li₂SnO₃ on the surface. Sn-doping and Li₂SnO₃ coating layer co-modification are helpful to optimize the ratio of Ni²⁺ and Ni³⁺, and to improve the conductivity of the cathode. The reversible capacity and rate capability of the cathode are improved by Sn-modification. The 3 mol% Sn-modified LiNi_0.5Co_0.2Mn_0.3O₂ sample maintained the reversible capacity of 146.8 mAh g⁻¹ at 5C, corresponding to 75.8% of its low-rate capacity (0.1C, 193.7mAh g⁻¹) and kept the reversible capacity of 157.3 mAh g⁻¹ with 88.4% capacity retention after 100 charge and discharge cycles at 1C rate between 2.7 and 4.6 V, showing the improved electrochemical property. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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18 pages, 4875 KiB

Open AccessArticle

3-Dimensional Porous Carbon with High Nitrogen Content Obtained from Longan Shell and Its Excellent Performance for Aqueous and All-Solid-State Supercapacitors

by Yuhao Liu, Xiaoxiao Qu, Guangxu Huang, Baolin Xing, Fengmei Zhang, Binbin Li, Chuanxiang Zhang and Yijun Cao

Nanomaterials 2020, 10(4), 808; https://doi.org/10.3390/nano10040808 - 23 Apr 2020

Cited by 25 | Viewed by 3428

Abstract

Three-dimensional porous carbon is considered as an ideal electrode material for supercapacitors (SCs) applications owing to its good conductivity, developed pore structure, and excellent connectivity. Herein, using longan shell as precursor, 3-dimensional porous carbon with abundant and interconnected pores and moderate heteroatoms were [...] Read more.

Three-dimensional porous carbon is considered as an ideal electrode material for supercapacitors (SCs) applications owing to its good conductivity, developed pore structure, and excellent connectivity. Herein, using longan shell as precursor, 3-dimensional porous carbon with abundant and interconnected pores and moderate heteroatoms were obtained via simple carbonization and potassium hydroxide (KOH) activation treatment. The electrochemical performances of obtained 3-dimensional porous carbon were investigated as electrode materials in symmetric SCs with aqueous and solid electrolytes. The optimized material that is named after longan shell 3-dimensional porous carbon 800 (LSPC800) possesses high porosity (1.644 cm³ g⁻¹) and N content (1.14 at %). In the three-electrode measurement, the LSPC800 displays an excellent capacitance value of 359 F g⁻¹. Besides, the LSPC800 also achieves splendid specific capacitance (254 F g⁻¹) in the two electrode system, while the fabricated SC employing 1 M Li₂SO₄ as electrolyte acquires ultrahigh power density (15930.38 W kg⁻¹). Most importantly, LSPC800 electrodes are further applied into the SC adopting the KOH/polyvinyl alcohol (PVA) gel electrolyte, which reaches up to an outstanding capacitance of 313 F g⁻¹ at 0.5 A g⁻¹. In addition, for the all-solid-state SC, its rate capability at 50 A g⁻¹ is 72.73% and retention at the 10,000th run is 93.64%. Evidently, this work is of great significance to the simple fabrication of 3-dimensional porous carbon and further opens up a way of improving the value-added utilization of biomass materials, as well as proving that the biomass porous carbons have immense potential for high-performance SCs application. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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16 pages, 2309 KiB

Open AccessArticle

2D/1D V₂O₅ Nanoplates Anchored Carbon Nanofibers as Efficient Separator Interlayer for Highly Stable Lithium–Sulfur Battery

by Zongtao Zhang, Guodong Wu, Haipeng Ji, Deliang Chen, Dengchao Xia, Keke Gao, Jianfei Xu, Bin Mao, Shasha Yi, Liying Zhang, Yu Wang, Ying Zhou, Litao Kang and Yanfeng Gao

Nanomaterials 2020, 10(4), 705; https://doi.org/10.3390/nano10040705 - 08 Apr 2020

Cited by 21 | Viewed by 3651

Abstract

Quick capacity loss due to the polysulfide shuttle effects is a critical challenge for high-performance lithium–sulfur (Li–S) batteries. Herein, a novel 2D/1D V₂O₅ nanoplates anchored carbon nanofiber (V-CF) interlayer coated on standard polypropylene (PP) separator is constructed, and a stabilization [...] Read more.

Quick capacity loss due to the polysulfide shuttle effects is a critical challenge for high-performance lithium–sulfur (Li–S) batteries. Herein, a novel 2D/1D V₂O₅ nanoplates anchored carbon nanofiber (V-CF) interlayer coated on standard polypropylene (PP) separator is constructed, and a stabilization mechanism derived from a quasi-confined cushion space (QCCS) that can flexibly accommodate the polysulfide utilization is demonstrated. The incorporation of the V-CF interlayer ensures stable electron and ion pathway, and significantly enhanced long-term cycling performances are obtained. A Li–S battery assembled with the V-CF membrane exhibited a high initial capacity of 1140.8 mAh·g⁻¹ and a reversed capacitance of 1110.2 mAh·g⁻¹ after 100 cycles at 0.2 C. A high reversible capacity of 887.2 mAh·g⁻¹ is also maintained after 500 cycles at 1 C, reaching an ultra-low decay rate of 0.0093% per cycle. The excellent electrochemical properties, especially the long-term cycling stability, can offer a promising designer protocol for developing highly stable Li–S batteries by introducing well-designed fine architectures to the separator. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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15 pages, 6471 KiB

Open AccessArticle

Supercapacitor Performance of Nickel-Cobalt Sulfide Nanotubes Decorated Using Ni Co-Layered Double Hydroxide Nanosheets Grown in Situ on Ni Foam

by Chen Xin, Li Ang, Farayi Musharavati, Fadi Jaber, Li Hui, Erfan Zalnezhad, Sungchul Bae, Kwan San Hui and Kwun Nam Hui

Nanomaterials 2020, 10(3), 584; https://doi.org/10.3390/nano10030584 - 23 Mar 2020

Cited by 20 | Viewed by 4967

Abstract

In this study, to fabricate a non-binder electrode, we grew nickel–cobalt sulfide (NCS) nanotubes (NTs) on a Ni foam substrate using a hydrothermal method through a two-step approach, namely in situ growth and an anion-exchange reaction. This was followed by the electrodeposition of [...] Read more.

In this study, to fabricate a non-binder electrode, we grew nickel–cobalt sulfide (NCS) nanotubes (NTs) on a Ni foam substrate using a hydrothermal method through a two-step approach, namely in situ growth and an anion-exchange reaction. This was followed by the electrodeposition of double-layered nickel-cobalt hydroxide (NCOH) over a nanotube-coated substrate to fabricate NCOH core-shell nanotubes. The final product is called NCS@NCOH herein. Structural and morphological analyses of the synthesized electrode materials were conducted via SEM and XRD. Different electrodeposition times were selected, including 10, 20, 40, and 80 s. The results indicate that the NCSNTs electrodeposited with NCOH nanosheets for 40 s have the highest specific capacitance (SC), cycling stability (2105 Fg⁻¹ at a current density of 2 Ag⁻¹), and capacitance retention (65.1% after 3,000 cycles), in comparison with those electrodeposited for 10, 20, and 80 s. Furthermore, for practical applications, a device with negative and positive electrodes made of active carbon and NCS@NCOH was fabricated, achieving a high-energy density of 23.73 Whkg⁻¹ at a power density of 400 Wkg⁻¹. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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17 pages, 6692 KiB

Open AccessArticle

Nitrogen Doped Intercalation TiO₂/TiN/Ti₃C₂T_x Nanocomposite Electrodes with Enhanced Pseudocapacitance

by Ben Yang, Yin She, Changgeng Zhang, Shuai Kang, Jin Zhou and Wei Hu

Nanomaterials 2020, 10(2), 345; https://doi.org/10.3390/nano10020345 - 18 Feb 2020

Cited by 23 | Viewed by 4422 | Retraction

Abstract

Layered two-dimensional titanium carbide (Ti₃C₂T_x), as an outstanding MXene member, has captured increasing attention in supercapacitor applications due to its excellent chemical and physical properties. However, the low gravimetric capacitance of Ti₃C₂T_x [...] Read more.

Layered two-dimensional titanium carbide (Ti₃C₂T_x), as an outstanding MXene member, has captured increasing attention in supercapacitor applications due to its excellent chemical and physical properties. However, the low gravimetric capacitance of Ti₃C₂T_x restricts its rapid development in such applications. Herein, this work demonstrates an effective and facile hydrothermal approach to synthesize nitrogen doped intercalation TiO₂/TiN/Ti₃C₂T_x with greatly improved gravimetric capacitance and excellent cycling stability. The hexamethylenetetramine (C₆H₁₂N₄) in hydrothermal environment acted as the nitrogen source and intercalants, while the Ti₃C₂T_x itself was the titanium source of TiO₂ and TiN. We tested the optimized nitrogen doped intercalation TiO₂/TiN/Ti₃C₂T_x electrodes in H₂SO₄, Li₂SO₄, Na₂SO₄, LiOH and KOH electrolytes, respectively. The electrode in H₂SO₄ electrolyte delivered the best electrochemical performance with high gravimetric capacitance of 361 F g⁻¹ at 1 A g⁻¹ and excellent cycling stability of 85.8% after 10,000 charge/discharge cycles. A systematic study of material characterization combined with the electrochemical performances disclosed that TiO₂/TiN nanoparticles, the introduction of nitrogen and the NH₄⁺ intercalation efficaciously increased the specific surface areas, which is beneficial for facilitating electrolyte ions transportation. Given the excellent performance, nitrogen doped intercalation TiO₂/TiN/Ti₃C₂T_x bodes well as a promising pseudocapacitor electrode for energy storage applications. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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10 pages, 5136 KiB

Open AccessArticle

Cu₂Se Nanoparticles Encapsulated by Nitrogen-Doped Carbon Nanofibers for Efficient Sodium Storage

by Le Hu, Chaoqun Shang, Eser Metin Akinoglu, Xin Wang and Guofu Zhou

Nanomaterials 2020, 10(2), 302; https://doi.org/10.3390/nano10020302 - 10 Feb 2020

Cited by 19 | Viewed by 3316

Abstract

Cu₂Se with high theoretical capacity and good electronic conductivity have attracted particular attention as anode materials for sodium ion batteries (SIBs). However, during electrochemical reactions, the large volume change of Cu₂Se results in poor rate performance and cycling stability. [...] Read more.

Cu₂Se with high theoretical capacity and good electronic conductivity have attracted particular attention as anode materials for sodium ion batteries (SIBs). However, during electrochemical reactions, the large volume change of Cu₂Se results in poor rate performance and cycling stability. To solve this issue, nanosized-Cu₂Se is encapsulated in 1D nitrogen-doped carbon nanofibers (Cu₂Se-NC) so that the unique structure of 1D carbon fiber network ensures a high contact area between the electrolyte and Cu₂Se with a short Na⁺ diffusion path and provides a protective matrix to accommodate the volume variation. The kinetic analysis and D_Na+ calculation indicates that the dominant contribution to the capacity is surface pseudocapacitance with fast Na⁺ migration, which guarantees the favorable rate performance of Cu₂Se-NC for SIBs. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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11 pages, 2716 KiB

Open AccessArticle

Binder-Free Nickel Oxide Lamellar Layer Anchored CoO_x Nanoparticles on Nickel Foam for Supercapacitor Electrodes

by Bohua Chen, Yu Zhong, Gengzhe Shen, Fengming Wang, Zhihao Liu, Mei Chen, Weijia Yang, Chi Zhang and Xin He

Nanomaterials 2020, 10(2), 194; https://doi.org/10.3390/nano10020194 - 22 Jan 2020

Cited by 6 | Viewed by 2972

Abstract

To enhance the connection of electroactive materials/current collector and accelerate the transport efficiency of the electrons, a binder-free electrode composed of nickel oxide anchored CoO_x nanoparticles on modified commercial nickel foam (NF) was developed. The nickel oxide layer with lamellar structure which [...] Read more.

To enhance the connection of electroactive materials/current collector and accelerate the transport efficiency of the electrons, a binder-free electrode composed of nickel oxide anchored CoO_x nanoparticles on modified commercial nickel foam (NF) was developed. The nickel oxide layer with lamellar structure which supplied skeleton to load CoO_x electroactive materials directly grew on the NF surface, leading to a tight connection between the current collector and electroactive materials. The fabricated electrode exhibits a specific capacitance of 475 F/g at 1 mA/cm². A high capacitance retention of 96% after 3000 cycles is achieved, attributed to the binding improvement at the current collector/electroactive materials interface. Moreover, an asymmetric supercapacitor with an operating voltage window of 1.4 V was assembled using oxidized NF anchored with cobalt oxide as the cathode and activated stainless steel wire mesh as the anode. The device achieves a maximum energy density of 2.43 Wh/kg and power density of 0.18 kW/kg, respectively. The modified NF substrate conducted by a facile and effective electrolysis process, which also could be applied to deposit other electroactive materials for the energy storage devices. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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12 pages, 3301 KiB

Open AccessArticle

Preparation of Nanocomposite Polymer Electrolyte via In Situ Synthesis of SiO₂ Nanoparticles in PEO

by Xinjie Tan, Yongmin Wu, Weiping Tang, Shufeng Song, Jianyao Yao, Zhaoyin Wen, Li Lu, Serguei V. Savilov, Ning Hu and Janina Molenda

Nanomaterials 2020, 10(1), 157; https://doi.org/10.3390/nano10010157 - 16 Jan 2020

Cited by 31 | Viewed by 5374

Abstract

Composite polymer electrolytes provide an emerging solution for new battery development by replacing liquid electrolytes, which are commonly complexes of polyethylene oxide (PEO) with ceramic fillers. However, the agglomeration of fillers and weak interaction restrict their conductivities. By contrast with the prevailing methods [...] Read more.

Composite polymer electrolytes provide an emerging solution for new battery development by replacing liquid electrolytes, which are commonly complexes of polyethylene oxide (PEO) with ceramic fillers. However, the agglomeration of fillers and weak interaction restrict their conductivities. By contrast with the prevailing methods of blending preformed ceramic fillers within the polymer matrix, here we proposed an in situ synthesis method of SiO₂ nanoparticles in the PEO matrix. In this case, robust chemical interactions between SiO₂ nanoparticles, lithium salt and PEO chains were induced by the in situ non-hydrolytic sol gel process. The in situ synthesized nanocomposite polymer electrolyte delivered an impressive ionic conductivity of ~1.1 × 10⁻⁴ S cm⁻¹ at 30 °C, which is two orders of magnitude higher than that of the preformed synthesized composite polymer electrolyte. In addition, an extended electrochemical window of up to 5 V vs. Li/Li⁺ was achieved. The Li/nanocomposite polymer electrolyte/Li symmetric cell demonstrated a stable long-term cycling performance of over 700 h at 0.01–0.1 mA cm⁻² without short circuiting. The all-solid-state battery consisting of the nanocomposite polymer electrolyte, Li metal and LiFePO₄ provides a discharge capacity of 123.5 mAh g⁻¹, a Coulombic efficiency above 99% and a good capacity retention of 70% after 100 cycles. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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14 pages, 3330 KiB

Open AccessArticle

Organic Thermoelectric Multilayers with High Stretchiness

by Chungyeon Cho and Jihun Son

Nanomaterials 2020, 10(1), 41; https://doi.org/10.3390/nano10010041 - 23 Dec 2019

Cited by 11 | Viewed by 2789

Abstract

A stretchable organic thermoelectric multilayer is achieved by alternately depositing bilayers (BL) of 0.1 wt% polyethylene oxide (PEO) and 0.03 wt% double walled carbon nanotubes (DWNT), dispersed with 0.1 wt% polyacrylic acid (PAA), by the layer-by-layer assembly technique. A 25 BL thin film [...] Read more.

A stretchable organic thermoelectric multilayer is achieved by alternately depositing bilayers (BL) of 0.1 wt% polyethylene oxide (PEO) and 0.03 wt% double walled carbon nanotubes (DWNT), dispersed with 0.1 wt% polyacrylic acid (PAA), by the layer-by-layer assembly technique. A 25 BL thin film (~500 nm thick), composed of a PEO/DWNT-PAA sequence, displays electrical conductivity of 19.6 S/cm and a Seebeck coefficient of 60 µV/K, which results in a power factor of 7.1 µW/m·K². The resultant nanocomposite exhibits a crack-free surface up to 30% strain and retains its thermoelectric performance, decreasing only 10% relative to the unstretched one. Even after 1000 cycles of bending and twisting, the thermoelectric behavior of this nanocomposite is stable. The synergistic combination of the elastomeric mechanical properties (originated from PEO/PAA systems) and thermoelectric behaviors (resulting from a three-dimensional conjugated network of DWNT) opens up the possibility of achieving various applications such as wearable electronics and sensors that require high mechanical compliance. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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11 pages, 1945 KiB

Open AccessArticle

Enhanced Humid Reliability of Organic Thermoelectrics via Crosslinking with Glycerol

by Jaeyun Kim, Jae Gyu Jang, Jeonghun Kwak, Jong-In Hong and Sung Hyun Kim

Nanomaterials 2019, 9(11), 1591; https://doi.org/10.3390/nano9111591 - 09 Nov 2019

Cited by 4 | Viewed by 2892

Abstract

Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has shown significant achievements in organic thermoelectrics (TEs) as an alternative for inorganic counterparts. However, PEDOT:PSS films have limited practical applications because their performance is sensitive to humidity. Crosslinking additives are utilized to improve the reliability of PEDOT:PSS film through enhancing [...] Read more.

Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has shown significant achievements in organic thermoelectrics (TEs) as an alternative for inorganic counterparts. However, PEDOT:PSS films have limited practical applications because their performance is sensitive to humidity. Crosslinking additives are utilized to improve the reliability of PEDOT:PSS film through enhancing hydrophobicity; among these, polyethylene glycol (PEG) is a widely-used additive. However, ether groups in PEG induce water molecules in the film through the hydrogen bond, which deteriorates the TE reliability. Here, we enhance the TE reliability of the PEDOT:PSS film using glycerol as an additive through the crosslinking reaction between the hydroxyl group in glycerol and the sulfonic acid in PEDOT:PSS. The TE reliability (1/Power factor (PF)) of PEG solution-treated PEDOT:PSS film (PEG solution-treated film) was 57% of its initial absolute value (0 h), after 288 h (two weeks) in a humid environment (95% relative humidity, 27 °C temperature). On the other hand, the glycerol solution-treated PEDOT:PSS film (glycerol solution-treated film) exhibited superior TE reliability and preserved 75% of its initial 1/PF. Furthermore, glycerol vapor treatment enabled the film to have stronger TE humid reliability, maintaining 82% of its initial 1/PF, with the same condition. This enhancement is attributed to the increased hydrophobicity and lower oxygen content of the glycerol vapor-treated PEDOT:PSS film (glycerol vapor-treated film), which provides little change in the chemical composition of PEDOT:PSS. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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13 pages, 1847 KiB

Open AccessArticle

Preparation of Highly Porous PAN-LATP Membranes as Separators for Lithium Ion Batteries

by Jagdeep Mohanta, O Hyeon Kwon, Jong Hyeok Choi, Yeo-Myeong Yun, Jae-Kwang Kim and Sang Mun Jeong

Nanomaterials 2019, 9(11), 1581; https://doi.org/10.3390/nano9111581 - 07 Nov 2019

Cited by 14 | Viewed by 4002

Abstract

Separators are a vital component to ensure the safety of lithium-ion batteries. However, the commercial separators employed in lithium ion batteries are inefficient due to their low porosity. In the present study, a simple electrospinning technique is adopted to prepare highly porous polyacrylonitrile [...] Read more.

Separators are a vital component to ensure the safety of lithium-ion batteries. However, the commercial separators employed in lithium ion batteries are inefficient due to their low porosity. In the present study, a simple electrospinning technique is adopted to prepare highly porous polyacrylonitrile (PAN)-based membranes with a higher concentration of lithium aluminum titanium phosphate (LATP) ceramic particles, as a viable alternative to the commercialized separators used in lithium ion batteries. The effect of the LATP particles on the morphology of the porous membranes is demonstrated through Field emission scattering electron microscopy. X-ray diffraction and Fourier transform infrared spectra studies suitably demonstrate the mixing of PAN and LATP particles in the polymer matrix. PAN with 30 wt% LATP (P-L30) exhibits an enhanced porosity of 90% and is more thermally stable, with the highest electrolyte uptake among all the prepared membranes. Due to better electrolyte uptake, the P-L30 membrane demonstrates an improved ionic conductivity of 1.7 mS/cm. A coin cell prepared with a P-L30 membrane and a LiFePO4 cathode demonstrates the highest discharge capacity of 158 mAh/g at 0.5C rate. The coin cell with the P-L30 membrane also displays good cycling stability by retaining 87% of the initial discharge capacity after 200 cycles of charging and discharging at 0.5C rate. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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14 pages, 5438 KiB

Open AccessArticle

Porous Hybrid Nanofibers Comprising ZnSe/CoSe₂/Carbon with Uniformly Distributed Pores as Anodes for High-Performance Sodium-Ion Batteries

by Sun Young Jeong and Jung Sang Cho

Nanomaterials 2019, 9(10), 1362; https://doi.org/10.3390/nano9101362 - 23 Sep 2019

Cited by 33 | Viewed by 3734

Abstract

Well-designed porous structured bimetallic ZnSe/CoSe₂/carbon composite nanofibers with uniformly distributed pores were prepared as anodes for sodium-ion batteries by electrospinning and subsequent simple heat-treatment processes. Size-controlled polystyrene (PS) nanobeads in the electrospinning solution played a key role in the formation and uniform distribution [...] Read more.

Well-designed porous structured bimetallic ZnSe/CoSe₂/carbon composite nanofibers with uniformly distributed pores were prepared as anodes for sodium-ion batteries by electrospinning and subsequent simple heat-treatment processes. Size-controlled polystyrene (PS) nanobeads in the electrospinning solution played a key role in the formation and uniform distribution of pores in the nanofiber structure, after the removal of selected PS nanobeads during the heat-treatment process. The porous ZnSe/CoSe₂/C composite nanofibers were able to release severe mechanical stress/strain during discharge–charge cycles, introduce larger contact area between the active materials and the electrolyte, and provide more active sites during cycling. The discharge capacity of porous ZnSe/CoSe₂/C composite nanofibers at the 10,000th cycle was 297 mA h g⁻¹, and the capacity retention measured from the second cycle was 81%. The final rate capacities of porous ZnSe/CoSe₂/C composite nanofibers were 438, 377, 367, 348, 335, 323, and 303 mA h g⁻¹ at current densities of 0.1, 0.5, 1, 3, 5, 7, and 10 A g⁻¹, respectively. At the higher current densities of 10, 20, and 30 A g⁻¹, the final rate capacities were 310, 222, and 141 mA h g⁻¹, respectively. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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