Editorial

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Open AccessEditorial

Special Issue: Materials for Electrochemical Capacitors and Batteries

by Jian-Gan Wang and Bingqing Wei

Materials 2017, 10(4), 438; https://doi.org/10.3390/ma10040438 - 22 Apr 2017

Cited by 4 | Viewed by 3825

Electrochemical capacitors and rechargeable batteries have received worldwide attention due to their excellent energy storage capability for a variety of applications. The rapid development of these technologies is propelled by the advanced electrode materials and new energy storage systems. It is believed that [...] Read more.

Electrochemical capacitors and rechargeable batteries have received worldwide attention due to their excellent energy storage capability for a variety of applications. The rapid development of these technologies is propelled by the advanced electrode materials and new energy storage systems. It is believed that research efforts can improve the device performance to meet the ever-increasing requirements of high energy density, high power density and long cycle life. This Special Issue aims to provide readers with a glimpse of different kinds of electrode materials for electrochemical capacitors and batteries. Full article

(This article belongs to the Special Issue Materials for Electrochemical Capacitors and Batteries)

Research

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8133 KiB

Open AccessArticle

A High Performance Lithium-Ion Capacitor with Both Electrodes Prepared from Sri Lanka Graphite Ore

by Xiaoyu Gao, Changzhen Zhan, Xiaoliang Yu, Qinghua Liang, Ruitao Lv, Guosheng Gai, Wanci Shen, Feiyu Kang and Zheng-Hong Huang

Materials 2017, 10(4), 414; https://doi.org/10.3390/ma10040414 - 14 Apr 2017

Cited by 23 | Viewed by 6041

Abstract

The natural Sri Lanka graphite (vein graphite) is widely-used as anode material for lithium-ion batteries (LIBs), due to its high crystallinity and low cost. In this work, graphitic porous carbon (GPC) and high-purity vein graphite (PVG) were prepared from Sri Lanka graphite ore [...] Read more.

The natural Sri Lanka graphite (vein graphite) is widely-used as anode material for lithium-ion batteries (LIBs), due to its high crystallinity and low cost. In this work, graphitic porous carbon (GPC) and high-purity vein graphite (PVG) were prepared from Sri Lanka graphite ore by KOH activation, and high temperature purification, respectively. Furthermore, a lithium-ion capacitor (LIC) is fabricated with GPC as cathode, and PVG as anode. The assembled GPC//PVG LIC shows a notable electrochemical performance with a maximum energy density of 86 W·h·kg⁻¹ at 150 W·kg⁻¹, and 48 W·h·kg⁻¹ at a high-power density of 7.4 kW·kg⁻¹. This high-performance LIC based on PVG and GPC is believed to be promising for practical applications, due to its low-cost raw materials and industrially feasible production. Full article

(This article belongs to the Special Issue Materials for Electrochemical Capacitors and Batteries)

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Open AccessArticle

Effects of Electrospun Carbon Nanofibers’ Interlayers on High-Performance Lithium–Sulfur Batteries

by Tianji Gao, TrungHieu Le, Ying Yang, Zhihao Yu, Zhenghong Huang and Feiyu Kang

Materials 2017, 10(4), 376; https://doi.org/10.3390/ma10040376 - 31 Mar 2017

Cited by 35 | Viewed by 8661

Abstract

Two different interlayers were introduced in lithium–sulfur batteries to improve the cycling stability with sulfur loading as high as 80% of total mass of cathode. Melamine was recommended as a nitrogen-rich (N-rich) amine component to synthesize a modified polyacrylic acid (MPAA). The electrospun [...] Read more.

Two different interlayers were introduced in lithium–sulfur batteries to improve the cycling stability with sulfur loading as high as 80% of total mass of cathode. Melamine was recommended as a nitrogen-rich (N-rich) amine component to synthesize a modified polyacrylic acid (MPAA). The electrospun MPAA was carbonized into N-rich carbon nanofibers, which were used as cathode interlayers, while carbon nanofibers from PAA without melamine was used as an anode interlayer. At the rate of 0.1 C, the initial discharge capacity with two interlayers was 983 mAh g⁻¹, and faded down to 651 mAh g⁻¹ after 100 cycles with the coulombic efficiency of 95.4%. At the rate of 1 C, the discharge capacity was kept to 380 mAh g⁻¹ after 600 cycles with a coulombic efficiency of 98.8%. It apparently demonstrated that the cathode interlayer is extremely effective at shutting down the migration of polysulfide ions. The anode interlayer induced the lithium ions to form uniform lithium metal deposits confined on the fiber surface and in the bulk to strengthen the cycling stability of the lithium metal anode. Full article

(This article belongs to the Special Issue Materials for Electrochemical Capacitors and Batteries)

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Open AccessArticle

Electrodeposited Porous Mn_1.5Co_1.5O₄/Ni Composite Electrodes for High-Voltage Asymmetric Supercapacitors

by Guan-Ting Pan, Siewhui Chong, Thomas C.-K. Yang and Chao-Ming Huang

Materials 2017, 10(4), 370; https://doi.org/10.3390/ma10040370 - 31 Mar 2017

Cited by 21 | Viewed by 4961

Abstract

Mesoporous Mn_1.5Co_1.5O₄ (MCO) spinel films were prepared directly on a conductive nickel (Ni) foam substrate via electrodeposition and an annealing treatment as supercapacitor electrodes. The electrodeposition time markedly influenced the surface morphological, textural, and supercapacitive properties of MCO/Ni [...] Read more.

Mesoporous Mn_1.5Co_1.5O₄ (MCO) spinel films were prepared directly on a conductive nickel (Ni) foam substrate via electrodeposition and an annealing treatment as supercapacitor electrodes. The electrodeposition time markedly influenced the surface morphological, textural, and supercapacitive properties of MCO/Ni electrodes. The (MCO/Ni)-15 min electrode (electrodeposition time: 15 min) exhibited the highest capacitance among three electrodes (electrodeposition times of 7.5, 15, and 30 min, respectively). Further, an asymmetric supercapacitor that utilizes (MCO/Ni)-15 min as a positive electrode, a plasma-treated activated carbon (PAC)/Ni electrode as a negative electrode, and carboxymethyl cellulose-lithium nitrate (LiNO₃) gel electrolyte (denoted as (PAC/Ni)//(MCO/Ni)-15 min) was fabricated. In a stable operation window of 2.0 V, the device exhibited an energy density of 27.6 Wh·kg⁻¹ and a power density of 1.01 kW·kg⁻¹ at 1 A·g⁻¹. After 5000 cycles, the specific energy density retention and power density retention were 96% and 92%, respectively, demonstrating exceptional cycling stability. The good supercapacitive performance and excellent stability of the (PAC/Ni)//(MCO/Ni)-15 min device can be ascribed to the hierarchical structure and high surface area of the (MCO/Ni)-15 min electrode, which facilitate lithium ion intercalation and deintercalation at the electrode/electrolyte interface and mitigate volume change during long-term charge/discharge cycling. Full article

(This article belongs to the Special Issue Materials for Electrochemical Capacitors and Batteries)

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Open AccessArticle

Coaxial MoS₂@Carbon Hybrid Fibers: A Low-Cost Anode Material for High-Performance Li-Ion Batteries

by Rui Zhou, Jian-Gan Wang, Hongzhen Liu, Huanyan Liu, Dandan Jin, Xingrui Liu, Chao Shen, Keyu Xie and Bingqing Wei

Materials 2017, 10(2), 174; https://doi.org/10.3390/ma10020174 - 13 Feb 2017

Cited by 32 | Viewed by 7678

Abstract

A low-cost bio-mass-derived carbon substrate has been employed to synthesize MoS₂@carbon composites through a hydrothermal method. Carbon fibers derived from natural cotton provide a three-dimensional and open framework for the uniform growth of MoS₂ nanosheets, thus hierarchically constructing coaxial architecture. [...] Read more.

A low-cost bio-mass-derived carbon substrate has been employed to synthesize MoS₂@carbon composites through a hydrothermal method. Carbon fibers derived from natural cotton provide a three-dimensional and open framework for the uniform growth of MoS₂ nanosheets, thus hierarchically constructing coaxial architecture. The unique structure could synergistically benefit fast Li-ion and electron transport from the conductive carbon scaffold and porous MoS₂ nanostructures. As a result, the MoS₂@carbon composites—when serving as anodes for Li-ion batteries—exhibit a high reversible specific capacity of 820 mAh·g⁻¹, high-rate capability (457 mAh·g⁻¹ at 2 A·g⁻¹), and excellent cycling stability. The use of bio-mass-derived carbon makes the MoS₂@carbon composites low-cost and promising anode materials for high-performance Li-ion batteries. Full article

(This article belongs to the Special Issue Materials for Electrochemical Capacitors and Batteries)

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Open AccessArticle

Deep Eutectic Solvent Synthesis of LiMnPO₄/C Nanorods as a Cathode Material for Lithium Ion Batteries

by Zhi Wu, Rong-Rong Huang, Hang Yu, Yong-Chun Xie, Xiao-Yan Lv, Jing Su, Yun-Fei Long and Yan-Xuan Wen

Materials 2017, 10(2), 134; https://doi.org/10.3390/ma10020134 - 06 Feb 2017

Cited by 28 | Viewed by 7493

Abstract

Olivine-type LiMnPO₄/C nanorods were successfully synthesized in a chloride/ethylene glycol-based deep eutectic solvent (DES) at 130 °C for 4 h under atmospheric pressure. As-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, [...] Read more.

Olivine-type LiMnPO₄/C nanorods were successfully synthesized in a chloride/ethylene glycol-based deep eutectic solvent (DES) at 130 °C for 4 h under atmospheric pressure. As-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and electrochemical tests. The prepared LiMnPO₄/C nanorods were coated with a thin carbon layer (approximately 3 nm thick) on the surface and had a length of 100–150 nm and a diameter of 40–55 nm. The prepared rod-like LiMnPO₄/C delivered a discharge capacity of 128 mAh·g⁻¹ with a capacity retention ratio of approximately 93% after 100 cycles at 1 C. Even at 5 C, it still had a discharge capacity of 106 mAh·g⁻¹, thus exhibiting good rate performance and cycle stability. These results demonstrate that the chloride/ethylene glycol-based deep eutectic solvents (DES) can act as a new crystal-face inhibitor to adjust the oriented growth and morphology of LiMnPO₄. Furthermore, deep eutectic solvents provide a new approach in which to control the size and morphology of the particles, which has a wide application in the synthesis of electrode materials with special morphology. Full article

(This article belongs to the Special Issue Materials for Electrochemical Capacitors and Batteries)

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Open AccessArticle

Facile Synthesis of V₂O₅ Hollow Spheres as Advanced Cathodes for High-Performance Lithium-Ion Batteries

by Xingyuan Zhang, Jian-Gan Wang, Huanyan Liu, Hongzhen Liu and Bingqing Wei

Materials 2017, 10(1), 77; https://doi.org/10.3390/ma10010077 - 18 Jan 2017

Cited by 31 | Viewed by 9057

Abstract

Three-dimensional V₂O₅ hollow structures have been prepared through a simple synthesis strategy combining solvothermal treatment and a subsequent thermal annealing. The V₂O₅ materials are composed of microspheres 2–3 μm in diameter and with a distinct hollow interior. [...] Read more.

Three-dimensional V₂O₅ hollow structures have been prepared through a simple synthesis strategy combining solvothermal treatment and a subsequent thermal annealing. The V₂O₅ materials are composed of microspheres 2–3 μm in diameter and with a distinct hollow interior. The as-synthesized V₂O₅ hollow microspheres, when evaluated as a cathode material for lithium-ion batteries, can deliver a specific capacity as high as 273 mAh·g⁻¹ at 0.2 C. Benefiting from the hollow structures that afford fast electrolyte transport and volume accommodation, the V₂O₅ cathode also exhibits a superior rate capability and excellent cycling stability. The good Li-ion storage performance demonstrates the great potential of this unique V₂O₅ hollow material as a high-performance cathode for lithium-ion batteries. Full article

(This article belongs to the Special Issue Materials for Electrochemical Capacitors and Batteries)

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Open AccessArticle

Pore-Structure-Optimized CNT-Carbon Nanofibers from Starch for Rechargeable Lithium Batteries

by Yongjin Jeong, Kyuhong Lee, Kinam Kim and Sunghwan Kim

Materials 2016, 9(12), 995; https://doi.org/10.3390/ma9120995 - 08 Dec 2016

Cited by 14 | Viewed by 4853

Abstract

Porous carbon materials are used for many electrochemical applications due to their outstanding properties. However, research on controlling the pore structure and analyzing the carbon structures is still necessary to achieve enhanced electrochemical properties. In this study, mesoporous carbon nanotube (CNT)-carbon nanofiber electrodes [...] Read more.

Porous carbon materials are used for many electrochemical applications due to their outstanding properties. However, research on controlling the pore structure and analyzing the carbon structures is still necessary to achieve enhanced electrochemical properties. In this study, mesoporous carbon nanotube (CNT)-carbon nanofiber electrodes were developed by heat-treatment of electrospun starch with carbon nanotubes, and then applied as a binder-free electrochemical electrode for a lithium-ion battery. Using the unique lamellar structure of starch, mesoporous CNT-carbon nanofibers were prepared and their pore structures were controlled by manipulating the heat-treatment conditions. The activation process greatly increased the volume of micropores and mesopores of carbon nanofibers by etching carbons with CO₂ gas, and the Brunauer-Emmett-Teller (BET) specific area increased to about 982.4 m²·g⁻¹. The activated CNT-carbon nanofibers exhibited a high specific capacity (743 mAh·g⁻¹) and good cycle performance (510 mAh·g⁻¹ after 30 cycles) due to their larger specific surface area. This condition presents many adsorption sites of lithium ions, and higher electrical conductivity, compared with carbon nanofibers without CNT. The research suggests that by controlling the heat-treatment conditions and activation process, the pore structure of the carbon nanofibers made from starch could be tuned to provide the conditions needed for various applications. Full article

(This article belongs to the Special Issue Materials for Electrochemical Capacitors and Batteries)

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