Special Issue "Advances in Electrochemical Energy Materials"

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Energy Materials".

Deadline for manuscript submissions: 31 December 2019.

Special Issue Editors

Guest Editor
Prof. Dr. Zhaoyang Fan Website E-Mail
Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX 79409-3102, USA
Interests: Semiconductor Materials, Electronic Devices, Nanomaterials, Energy Storage
Guest Editor
Assoc. Prof. Shiqi Li E-Mail
College of Electronic Information, Hangzhou Dianzi University, Hangzhou 310018, China
Interests: lithium–sulfur batteries; lithium-ion batteries; supercapacitors; microwave chemistry

Special Issue Information

Dear Colleagues,

Electrochemical energy storage and conversion systems are becoming essential for electrified transportation, integration of intermittent renewable energy into grids, non-fossil and green fuel production, and many other energy or power applications. The electrode materials and structures, in addition to the liquid or solid electrolytes, play key roles in supporting a multitude of coupled physicochemical processes that include electronic, ionic, and diffusive transport in electrode and electrolyte phases, electrochemical reactions and material phase changes, as well as mechanical and thermal stresses, thus determining the storage energy density and power density, conversion efficiency, performance lifetime, and system cost and safety. Different material chemistries and multiscale porous structures are being investigated towards high performance and low cost. The aim of this Special Issue is to report recent advances related to materials used either in electrochemical energy storage, which encompasses supercapacitors and Li ion, Na ion, or other rechargeable batteries, or in electrochemical energy conversion, which includes electrocatalysts, green fuel production, fuel cells, etc. We are confident that publication of such a Special Issue will stimulate the imagination of researchers to develop advanced materials to further enhance the performance of electrochemical energy devices and put forward their practical application.

It is our pleasure to invite you to submit a manuscript reporting novel materials and structures, their electrochemical behaviors, fundamental mechanisms, novel device concepts, as well as other related topics for this Special Issue. Full papers, communications, and reviews are all welcome.

Prof. Zhaoyang Fan
Assoc. Prof. Shiqi Li
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • rechargable betteries
  • supercapacitors
  • fuel cells
  • electrocatalyst
  • electrode materials
  • nanostructure
  • electrochemical energy
  • energy storage
  • energy conversion

Published Papers (9 papers)

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Research

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Open AccessArticle
Development of ZIF-Derived Nanoporous Carbon and Cobalt Sulfide-Based Electrode Material for Supercapacitor
Materials 2019, 12(18), 2940; https://doi.org/10.3390/ma12182940 - 11 Sep 2019
Abstract
Zeolitic Imidazolate Framework (ZIF-67) was prepared in two different solvents—water and methanol. Nanoporous carbon was derived from ZIF-67 via pyrolysis in an inert atmosphere. Anion exchange step of sulfidation on the synthesized material has a great influence on the structure and properties. Structural [...] Read more.
Zeolitic Imidazolate Framework (ZIF-67) was prepared in two different solvents—water and methanol. Nanoporous carbon was derived from ZIF-67 via pyrolysis in an inert atmosphere. Anion exchange step of sulfidation on the synthesized material has a great influence on the structure and properties. Structural morphology and thermal stability were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy dispersive x-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET), and thermogravimetric (TG) analysis. The electrochemical analysis was evaluated by cyclic voltammetry, chronopotentiometry, and impedance analysis. The as-prepared nanoporous carbon and cobalt sulfide (NPC/CS) electrode material (water) in 2M KOH electrolyte solution exhibit high specific capacitance of 677 F/g. The excellent electrochemical performance of the NPC/CS was attributed to its hierarchical structure. This functionalized ZIF driven strategy paves the way to the preparation of various metal oxide and metal sulfide-based nanoheterostructures by varying the type of metal. Full article
(This article belongs to the Special Issue Advances in Electrochemical Energy Materials)
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Open AccessArticle
Enhanced Electrochemical Performances of Cobalt-Doped Li2MoO3 Cathode Materials
Materials 2019, 12(6), 843; https://doi.org/10.3390/ma12060843 - 13 Mar 2019
Abstract
Co-doped Li2MoO3 was successfully synthesized via a solid phase method. The impacts of Co-doping on Li2MoO3 have been analyzed by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy [...] Read more.
Co-doped Li2MoO3 was successfully synthesized via a solid phase method. The impacts of Co-doping on Li2MoO3 have been analyzed by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) measurements. The results show that an appropriate amount of Co ions can be introduced into the Li2MoO3 lattices, and they can reduce the particle sizes of the cathode materials. Electrochemical tests reveal that Co-doping can significantly improve the electrochemical performances of the Li2MoO3 materials. Li2Mo0.90Co0.10O3 presents a first-discharge capacity of 220 mAh·g−1, with a capacity retention of 63.6% after 50 cycles at 5 mA·g−1, which is much better than the pristine samples (181 mAh·g−1, 47.5%). The enhanced electrochemical performances could be due to the enhancement of the structural stability, and the reduction in impedance, due to the Co-doping. Full article
(This article belongs to the Special Issue Advances in Electrochemical Energy Materials)
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Open AccessArticle
Simulation-driven Selection of Electrode Materials Based on Mechanical Performance for Lithium-Ion Battery
Materials 2019, 12(5), 831; https://doi.org/10.3390/ma12050831 - 12 Mar 2019
Abstract
Experimental and numerical studies have shown that mechanical loading associated with lithiation/delithiation may limit the useful life of battery electrode materials. The paper presents an approach to parameterize and compare electrode material performance based on mechanical stability. A mathematical model was developed to [...] Read more.
Experimental and numerical studies have shown that mechanical loading associated with lithiation/delithiation may limit the useful life of battery electrode materials. The paper presents an approach to parameterize and compare electrode material performance based on mechanical stability. A mathematical model was developed to determine particle deformation and stress fields based upon an elastic-perfectly plastic constitutive response. Mechanical deformation was computed by combining the stress equilibrium equations with the electrochemical diffusion of lithium ions into the electrode particle. The result provided a time developing stress field which shifts from purely elastic to partially plastic deformation as the lithium-ion diffuses into the particle. The model was used to derive five merit indices that parameterize mechanical stability of electrode materials. The merit indices were used to analyze the mechanical stability for the six candidate electrode materials—three for anode materials and three for the cathode material. Finally, the paper suggests ways to improve the mechanical performance of electrode materials and identifies mechanical properties that need to be considered for selection and optimal design of electrode materials. Full article
(This article belongs to the Special Issue Advances in Electrochemical Energy Materials)
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Open AccessArticle
Super-Capacitive Performance of Manganese Dioxide/Graphene Nano-Walls Electrodes Deposited on Stainless Steel Current Collectors
Materials 2019, 12(3), 483; https://doi.org/10.3390/ma12030483 - 04 Feb 2019
Abstract
Graphene nano-walls (GNWs) are promising materials that can be used as an electrode in electrochemical devices. We have grown GNWs by inductively-coupled plasma-enhanced chemical vapor deposition on stainless steel (AISI304) substrate. In order to enhance the super-capacitive properties of the electrodes, we have [...] Read more.
Graphene nano-walls (GNWs) are promising materials that can be used as an electrode in electrochemical devices. We have grown GNWs by inductively-coupled plasma-enhanced chemical vapor deposition on stainless steel (AISI304) substrate. In order to enhance the super-capacitive properties of the electrodes, we have deposited a thin layer of MnO2 by electrodeposition method. We studied the effect of annealing temperature on the electrochemical properties of the samples between 70 °C and 600 °C. Best performance for supercapacitor applications was obtained after annealing at 70 °C with a specific capacitance of 104 F·g−1 at 150 mV·s−1 and a cycling stability of more than 14k cycles with excellent coulombic efficiency and 73% capacitance retention. Electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge measurements reveal fast proton diffusion (1.3 × 10−13 cm2·s−1) and surface redox reaction after annealing at 70 °C. Full article
(This article belongs to the Special Issue Advances in Electrochemical Energy Materials)
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Open AccessArticle
Enhanced Electrochemical Performance of Li1.27Cr0.2Mn0.53O2 Layered Cathode Materials via a Nanomilling-Assisted Solid-state Process
Materials 2019, 12(3), 468; https://doi.org/10.3390/ma12030468 - 03 Feb 2019
Abstract
Li1.27Cr0.2Mn0.53O2 layered cathodic materials were prepared by a nanomilling-assisted solid-state process. Whole-pattern refinement of X-ray diffraction (XRD) data revealed that the samples are solid solutions with layered α-NaFeO2 structure. SEM observation of the prepared powder [...] Read more.
Li1.27Cr0.2Mn0.53O2 layered cathodic materials were prepared by a nanomilling-assisted solid-state process. Whole-pattern refinement of X-ray diffraction (XRD) data revealed that the samples are solid solutions with layered α-NaFeO2 structure. SEM observation of the prepared powder displayed a mesoporous nature composed of tiny primary particles in nanoscale. X-ray photoelectron spectroscopy (XPS) studies on the cycled electrodes confirmed that triple-electron-process of the Cr3+/Cr6+ redox pair, not the two-electron-process of Mn redox pair, dominants the electrochemical process within the cathode material. Capacity test for the sample revealed an initial discharge capacity of 195.2 mAh·g−1 at 0.1 C, with capacity retention of 95.1% after 100 cycles. EIS investigation suggested that the high Li ion diffusion coefficient (3.89 × 10−10·cm2·s−1), caused by the mesoporous nature of the cathode powder, could be regarded as the important factor for the excellent performance of the Li1.27Cr0.2Mn0.53O2 layered material. The results demonstrated that the cathode material prepared by our approach is a good candidate for lithium-ion batteries. Full article
(This article belongs to the Special Issue Advances in Electrochemical Energy Materials)
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Open AccessArticle
Preparation of LiFePO4/C Cathode Materials via a Green Synthesis Route for Lithium-Ion Battery Applications
Materials 2018, 11(11), 2251; https://doi.org/10.3390/ma11112251 - 12 Nov 2018
Abstract
In this work, LiFePO4/C composite were synthesized via a green route by using Iron (III) oxide (Fe2O3) nanoparticles, Lithium carbonate (Li2CO3), glucose powder and phosphoric acid (H3PO4) solution as [...] Read more.
In this work, LiFePO4/C composite were synthesized via a green route by using Iron (III) oxide (Fe2O3) nanoparticles, Lithium carbonate (Li2CO3), glucose powder and phosphoric acid (H3PO4) solution as raw materials. The reaction principles for the synthesis of LiFePO4/C composite were analyzed, suggesting that almost no wastewater and air polluted gases are discharged into the environment. The morphological, structural and compositional properties of the LiFePO4/C composite were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Raman and X-ray photoelectron spectroscopy (XPS) spectra coupled with thermogravimetry/Differential scanning calorimetry (TG/DSC) thermal analysis in detail. Lithium-ion batteries using such LiFePO4/C composite as cathode materials, where the loading level is 2.2 mg/cm2, exhibited excellent electrochemical performances, with a discharge capability of 161 mA h/g at 0.1 C, 119 mA h/g at 10 C and 93 mA h/g at 20 C, and a cycling stability with 98.0% capacity retention at 1 C after 100 cycles and 95.1% at 5 C after 200 cycles. These results provide a valuable approach to reduce the manufacturing costs of LiFePO4/C cathode materials due to the reduced process for the polluted exhaust purification and wastewater treatment. Full article
(This article belongs to the Special Issue Advances in Electrochemical Energy Materials)
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Open AccessArticle
Structure and Electrochemical Properties of Mn3O4 Nanocrystal-Coated Porous Carbon Microfiber Derived from Cotton
Materials 2018, 11(10), 1987; https://doi.org/10.3390/ma11101987 - 15 Oct 2018
Cited by 2
Abstract
Biomorphic Mn3O4 nanocrystal/porous carbon microfiber composites were hydrothermally fabricated and subsequently calcined using cotton as a biotemplate. The as-prepared material exhibited a specific capacitance of 140.8 F·g−1 at 0.25 A·g−1 and an excellent cycle stability with a capacitance [...] Read more.
Biomorphic Mn3O4 nanocrystal/porous carbon microfiber composites were hydrothermally fabricated and subsequently calcined using cotton as a biotemplate. The as-prepared material exhibited a specific capacitance of 140.8 F·g−1 at 0.25 A·g−1 and an excellent cycle stability with a capacitance retention of 90.34% after 5000 cycles at 1 A·g−1. These characteristics were attributed to the introduction of carbon fiber, the high specific surface area, and the optimized microstructure inherited from the biomaterial. Full article
(This article belongs to the Special Issue Advances in Electrochemical Energy Materials)
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Open AccessArticle
High Electrochemical Performance of Nanotube Structured ZnS as Anode Material for Lithium–Ion Batteries
Materials 2018, 11(9), 1537; https://doi.org/10.3390/ma11091537 - 26 Aug 2018
Cited by 2
Abstract
By using ZnO nanorods as an ideal sacrificial template, one-dimensional (1-D) ZnS nanotubes with a mean diameter of 10 nm were successfully synthesized by hydrothermal method. The phase composition and microstructure of the ZnS nanotubes were characterized by using XRD (X-ray diffraction), SEM [...] Read more.
By using ZnO nanorods as an ideal sacrificial template, one-dimensional (1-D) ZnS nanotubes with a mean diameter of 10 nm were successfully synthesized by hydrothermal method. The phase composition and microstructure of the ZnS nanotubes were characterized by using XRD (X-ray diffraction), SEM (scanning electron micrograph), and TEM (transmission electronic microscopy) analysis. X-ray photoelectron spectroscopy (XPS) and nitrogen sorption isotherms measurements were also used to study the information on the surface chemical compositions and specific surface area of the sample. The prepared ZnS nanotubes were used as anode materials in lithium-ion batteries. Results show that the ZnS nanotubes deliver an impressive prime discharge capacity as high as 950 mAh/g. The ZnS nanotubes also exhibit an enhanced cyclic performance. Even after 100 charge/discharge cycles, the discharge capacity could still remain at 450 mAh/g. Moreover, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements were also carried out to evaluate the ZnS electrodes. Full article
(This article belongs to the Special Issue Advances in Electrochemical Energy Materials)
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Review

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Open AccessFeature PaperReview
AC-Filtering Supercapacitors Based on Edge Oriented Vertical Graphene and Cross-Linked Carbon Nanofiber
Materials 2019, 12(4), 604; https://doi.org/10.3390/ma12040604 - 18 Feb 2019
Abstract
There is strong interest in developing high-frequency (HF) supercapacitors or electrochemical capacitors (ECs), which can work at the hundreds to kilo hertz range for line-frequency alternating current (AC) filtering in the substitution of bulky aluminum electrolytic capacitors, with broad applications in the power [...] Read more.
There is strong interest in developing high-frequency (HF) supercapacitors or electrochemical capacitors (ECs), which can work at the hundreds to kilo hertz range for line-frequency alternating current (AC) filtering in the substitution of bulky aluminum electrolytic capacitors, with broad applications in the power and electronic fields. Although great progress has been achieved in the studies of electrode materials for ECs, most of them are not suitable to work in this high frequency range because of the slow electrochemical processes involved. Edge-oriented vertical graphene (VG) networks on 3D scaffolds have a unique structure that offers straightforward pore configuration, reasonable surface area, and high electronic conductivity, thus allowing the fabrication of HF-ECs. Comparatively, highly conductive freestanding cross-linked carbon nanofibers (CCNFs), derived from bacterial cellulose in a rapid plasma pyrolysis process, can also provide a large surface area but free of rate-limiting micropores, and are another good candidate for HF-ECs. In this mini review, advances in these fields are summarized, with emphasis on our recent contributions in the study of these materials and their electrochemical properties including preliminary demonstrations of HF-ECs for AC line filtering and pulse power storage applications. Full article
(This article belongs to the Special Issue Advances in Electrochemical Energy Materials)
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