1,721,494 research outputs found
Batteries Based on Metal‐Free Carbon Electrocatalysts
No full textMetal-CO2 batteries have attracted much attention owing to their high energy density and use of greenhouse CO2 waste as the energy source. However, the increasing cost of lithium and the low discharge potential of Na-CO2 batteries create obstacles for practical applications of Li/Na-CO2 batteries. Recently, earth-abundant potassium ions have attracted considerable interest as fast ionic charge carriers for electrochemical energy storage. Herein, we report the first K-CO2 battery with a carbon-based metal-free electrocatalyst. The battery shows a higher theoretical discharge potential (E⊖ =2.48 V) than that of Na-CO2 batteries (E⊖ =2.35 V) and can operate for more than 250 cycles (1500 h) with a cutoff capacity of 300 mA h g-1 . Combined DFT calculations and experimental observations revealed a reaction mechanism involving the reversible formation and decomposition of P121 /c1-type K2 CO3 at the efficient carbon-based catalyst.Wenchao Zhang, Chuangang Hu, Zaiping Guo, Liming Da
Isotope-mass-dependent thermal effects of cathode-anode crosstalk in a rechargeable lithium-sulfur battery
No full textBrief CommunicationsAbstract not availableXi-Xi Feng, Yu-Hui Zhu, Hua Guo, Chao-Hui Zhang, Zaiping Guo, Sen Xi
Rechargeable Potassium–Selenium Batteries
No full textFirst published: 06 May 2021Rechargeable potassium–selenium (K–Se) batteries, as an emerging electrochemical energy storage system, has recently captured intensive attention due to the desirable natural abundance and low redox potential of elemental potassium as well as the relatively high electronic conductivity and impressive theoretical volumetric capacity of elemental selenium. Although great progress on cathode materials design and electrochemical performance improvement has been made, K–Se batteries are still confronted with a series of key challenges, including low reactive activity, shuttle effect, volume expansion, potassium dendrite growth, and high chemical activity of potassium metal. The recent advances in rechargeable K–Se batteries are comprehensively summarized with an emphasis on discussing the electrochemical mechanisms and central challenges, presenting the synthesis, properties, and electrochemical performance of selenium-based cathode materials, and extending potential tactics for tackling the key issues and developmental directions for future research.Xiang Long Huang, Zaiping Guo, Shi Xue Dou, Zhiming M. Wan
Developing high-voltage spinel LiNi(0)<NON-ASCII>⋅(8901)<NON-ASCII>(5)Mn(1)<NON-ASCII>⋅(8901)<NON-ASCII>(5)O(4) cathodes for high-energy-density lithium-ion batteries: current achievements and future prospects
No full textThis paper highlights current research progress and future prospects of high-voltage spinel LiNi0.5Mn1.5O4 cathode for next-generation high-enegy-density lithium-ion batteries.Gemeng Liang, Vanessa K. Peterson, Khay Wai See, Zaiping Guo and Wei Kong Pan
Synthesis and electrochemical properties of non-stoichiometric Li–Mn-spinel (Li1.02MxMn1.95O4−yFy) for lithium ion battery application
No full textNon-stoichiometric spinel compounds Li1.02MxMn1.95O4−yFy (M = Co, Y, and Ga) were prepared for the first time by the rheological phase reaction method. The Li1.02MxMn1.95O4−yFy samples were characterized by X-ray diffraction, while the particle size and shape of the Li1.02MxMn1.95O4−yFy were observed by scanning and transmission electron microscopy. The as-prepared samples were used as cathode materials in lithium-ion batteries, their electrochemical properties were tested, and the results showed that the non-stoichiometric spinels Li1.02MxMn1.95O4−yFy had better cycling performance than pure LiMn2O4. In addition, among the different non-stoichiometric spinel samples, the Li1.02Mn1.95Co0.02Y0.01Ga0.01O3.97F0.03 sample not only had higher charge/discharge capacity, but also showed the best cycling performance, as the loss of its capacity was only 7% after 100 cycles. The possible reasons for the outstanding electrical properties of Li1.02Mn1.95Co0.02Y0.01Ga0.01O3.97F0.03 are also discussed.Chuanqi Feng, Hua Li, Chaofeng Zhang, Zaiping Guo, Huimin Wu, Jing Tan
Understanding Rechargeable Battery Function Using In Operando Neutron Powder Diffraction
No full textThe performance of rechargeable batteries is influenced by the structural and phase changes of components during cycling. Neutron powder diffraction (NPD) provides unique and useful information concerning the structure-function relation of battery components and can be used to study the changes to component phase and structure during battery cycling, known as in operando measurement studies. The development and use of NPD for in operando measurements of batteries is summarized along with detailed experimental approaches that impact the insights gained by these. A summary of the information gained concerning battery function using in operando NPD measurements is provided, including the structural and phase evolution of electrode materials and charge-carrying ion diffusion pathways through these, which are critical to the development of battery technology.Gemeng Liang, Christophe Didier, Zaiping Guo, Wei Kong Pang and Vanessa K. Peterso
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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