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Kang Du

Bio: Kang Du is an academic researcher from National University of Singapore. The author has contributed to research in topics: Electrolyte & Anode. The author has an hindex of 3, co-authored 5 publications receiving 71 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a new phase of Na-rich and all Fe Prussian Blue Analogue, monoclinic Na2Fe2(CN)6.2H2O, is reported as a potential cathode for such grid-storage sodium-ion batteries.
Abstract: One of the key requirements of large-scale grid-storage systems is development of inexpensive and safe batteries. Sodium-ion batteries using earth-abundant Fe or Ti based cathodes and anodes would be ideal candidates for such storage systems. Herein, a new phase of Na-rich and all Fe Prussian Blue Analogue, monoclinic Na2Fe2(CN)6.2H2O, is reported as a potential cathode for such grid-storage sodium-ion batteries. This water-insoluble and air-stable cathode can deliver 85 mAh g−1 at an average discharge voltage of 3 V vs Na/Na+ with excellent cycle life (3,000 cycles). Many facets about its sodium storage characteristics are discussed with particular emphasis on the role of interstitial water on the sodium storage performance and its conversion to the dehydrated rhombohedral phase. Its compatibility with a newly developed non-flammable glyme-based liquid electrolyte, 1M NaBF4 in tetraglyme, is also disclosed along with general electrochemical and thermal characterization of this electrolyte for sodium-ion battery application. Finally, three different types of full cells are revealed with either monoclinic or rhombohedral phase as cathode and graphite or the recently reported Na2Ti3O7 Na3-xTi3O7 pathway of Na2Ti3O7 as anode. Full cell energy densities of 70–90 Wh kg−1 (using cumulative cathode and anode weights) could be obtained without any pre-cycling steps. This new cathode and safe electrolyte may hold great promise toward development of inexpensive, non-flammable and highly stable grid-storage sodium-ion batteries.

75 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a comprehensive study of choice of electrolyte, anode and cathode to develop commercially viable non-flammable sodium-ion battery, and compare storage performance, thermal stability and SEI formation with those obtained using carbonate-based electrolyte.

29 citations

Journal ArticleDOI
TL;DR: In this article, an ether-based non-flammable electrolyte, 1 M NaBF4 in tetraglyme, is tested for sodium storage using a non-carbonaceous anode material Na2Ti3O7/C, and the results are compared with those obtained with the popularly used carbonate-based electrolyte.
Abstract: In order to become commercially viable, sodium-ion batteries need to deliver long cycle life with good capacity and energy density while still ensuring safety. Electrolyte plays a key role forming solid electrolyte interphase (SEI) layers at low potential, which affects the thermal stability and cycle life of the anode materials under consideration. In this study, an ether-based non-flammable electrolyte, 1 M NaBF4 in tetraglyme, is tested for sodium storage using a non-carbonaceous anode material Na2Ti3O7/C, and the results are compared with those obtained with the popularly used carbonate-based electrolyte, 1 M NaClO4 in ethylene carbonate (EC) and propylene carbonate (PC) (v/v = 1:1). The Na2Ti3O7/C versus Na cells using 1 M NaBF4 in tetraglyme show a much higher first cycle Coulombic efficiency (73%) than those using 1 M NaClO4 in EC/PC (33%). Thermal stability studies using differential scanning calorimetry (DSC) conclusively show that Na2Ti3O7/C electrodes cycled with 1 M NaBF4 in tetraglyme are more thermally stable than the one cycled with 1 M NaClO4 in EC/PC. Further investigations on the formation of SEI layers were performed using attenuated total reflection-Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, and DSC studies. These studies unambiguously demonstrate that the SEI formed on Na2Ti3O7/C using 1 M NaBF4 in tetraglyme is not only less resistive but also more stable than the SEI formed using 1 M NaClO4 in EC/PC.

13 citations

Patent
26 Oct 2017
TL;DR: In this article, a non-flammable sodium-ion battery having a cathode and an anode and which uses an electrolyte that includes NaBF 4 and a glyme solvent, where the battery has an average voltage of from 1.5 V to 6.0 V.
Abstract: Disclosed herein is a non-flammable sodium-ion battery having a cathode and an anode and which uses an electrolyte that includes NaBF 4 and a glyme solvent, where the battery has an average voltage of from 1.5 V to 6.0 V and has a coulombic efficiency after 5 charge/discharge cycles of at least 90%.

1 citations


Cited by
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TL;DR: A review of the most recent developments in the field of green binders for batteries and supercapacitors can be found in this paper, where the authors discuss how they could decrease cost and environmental impact, and yet improve the performance of electrochemical energy devices.
Abstract: In this review, we discuss the most recent developments in the field of green binders for batteries and supercapacitors and explain how they could decrease cost and environmental impact, and yet improve the performance of electrochemical energy devices. The different classes of green binders reported to date in the literature are firstly classified according to their processability (the solvent required for electrode manufacturing), chemical composition (F-free), and natural availability (synthetic or bio-derived). The benefits originating from their employment are analysed for different devices. The most popular lithium-ion batteries are thoroughly discussed both from the anode and the cathode side. While high capacity Si-based anodes benefit from enhanced cyclability due to the interaction between the active particles’ surface and the functional groups of, e.g., polysaccharides such as carboxymethyl cellulose and alginate, the transition to water-processable cathodes is certainly more challenging. In particular, strategies to suppress the aluminium corrosion affecting most lithiated transition metal oxides are discussed. Despite the much more limited literature available, the role of the binder is increasingly recognized in the emerging field of lithium–sulphur and sodium-ion batteries, and electrochemical double layer capacitors and, therefore, here discussed as well.

326 citations

Journal ArticleDOI
TL;DR: In this paper, the authors compared Na and Li batteries in terms of fundamental principles and specific materials, and assessed the performance of commercial prototype sodium cells, and concluded that Na cells offer realistic alternatives that are competitive with some Li cells.
Abstract: Na-based batteries have shown substantial progress in recent years and are promising candidates for mitigating the supply risks associated with Li-based batteries. In this Review, Na and Li batteries are compared in terms of fundamental principles and specific materials. Principles for the rational design of a Na battery architecture are discussed. Recent prototypes are surveyed to demonstrate that Na cells offer realistic alternatives that are competitive with some Li cells in terms of performance. Sodium batteries are promising candidates for mitigating the supply risks associated with lithium batteries. This Review compares the two technologies in terms of fundamental principles and specific materials, and assesses the performance of commercial prototype sodium cells.

294 citations

Journal ArticleDOI
25 May 2018-iScience
TL;DR: In this review, a general summary and evaluation of the applications ofPBAs for rechargeable batteries are given and an outlook toward the further development of PBAs in electrochemical energy storage is included.

281 citations

Journal ArticleDOI
01 Apr 2018-Small
TL;DR: This review article conducts a comprehensive review of "external" factors to electrodes of Na-ion batteries, especially by looking into their correlation with electrochemical properties, such as cycle life, and first cycle coulombic efficiency.
Abstract: Through intense effort in recent years, knowledge of Na-ion batteries has been advanced significantly, pertaining to electrodes. Often, such progress has been accompanied by using a convenient choice of electrolyte or binder. Nevertheless, it has been witnessed that "external" factors to electrodes, such as electrolytes, solid electrolyte interphase, and binders, affect the functions of electrodes profoundly. And generally, certain types of electrodes favor some electrolytes or binders. With a rapidly increasing number of publications in the area, trends in terms of electrolytes and binders are possibly exploitable. Unfortunately, the field has yet to see a review article that devotes itself to these nonelectrode aspects of Na-ion batteries. Here, the gap is filled by conducting a comprehensive review of these nonelectrode external factors, especially by looking into their correlation with electrochemical properties, such as cycle life, and first cycle coulombic efficiency. Not only are the representative reports reviewed, but also quantitative analyses on the database that are constructed are provided. With such analyses, some new data-driven perspectives are postulated, which are of great value to the community.

212 citations