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440 results on '"Jian, Zengyun"'

35. Nanostructured C@CuS Core–Shell Framework with High Lithium-Ion Storage Performance.

Author

Jin, Changqing, Peng, Zaidong, Wei, Yongxing, Nan, Ruihua, Yang, Zhong, Jian, Zengyun, and Ding, Qingping

Subjects
PRECIPITATION (Chemistry), COPPER sulfide, COMPOSITE construction, NANOSTRUCTURED materials, LITHIUM-ion batteries, METAL sulfides
Abstract

In this study, we have synthesized a nanostructured core–shell framework of carbon-coated copper sulfide (C@CuS) through a one-step precipitation technique. The carbon sphere template facilitated the nucleation of CuS nanostructures. The synthesized nanocomposites have demonstrated remarkable lithium-ion storage capabilities when utilized as an anode in lithium-ion batteries. Notably, they exhibit an impressive rate capability of 314 mAh g−1 at a high current density of 5000 mA g−1, along with excellent long-term cycle stability, maintaining 463 mAh g−1 at 1000 mA g−1 after 800 cycles. This superior performance is due to the core–shell architecture of the composite, where the carbon core enhances the conductivity of CuS nanoparticles and mitigates volume expansion, thus preventing capacity loss. Our study not only elucidates the significance of carbon in the construction of nano-heterojunctions or composite electrodes but also presents a practical approach to significantly boost the electrochemical performance of CuS and other metal sulfides. [ABSTRACT FROM AUTHOR]

Published
2024
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43. Non-isothermal crystallization behavior of Cr50Fe6Co7Mo14C15B6Y2metallic glass with super high content of Cr and integrated merits

Author

Li, Jiahui, Fan, Xiaorong, Geng, Yinghui, Zhang, Limei, Huang, Xiaorong, Xie, Hengyue, Xu, Tao, Li, Meng, Zhuo, Longchao, Liu, Zhenting, and Jian, Zengyun

Abstract

In present work, non-isothermal crystallization behavior for novel Cr50Fe6Co7Mo14C15B6Y2metallic glass (MG) with super high content of Cr and excellent merits was investigated by differential scanning calorimeter and X-ray diffraction. Both of the Kissinger and Ozawa methods show that the present glass transition is much harder than other transitions for a much larger apparent activation energy (E). While, the growth process of present second crystallization event is the easiest process, since it possesses the smallest E. Meanwhile, the local activation energy established by Kissinger-Akahira-Sunose and Ozawa-Flynn-Wall methods both exhibit a trend of increasing to the maximum value at first and then gradual decrease until the finish of the crystallization, indicating that the difficulty increases until to the maximum at first and then gradually decreases during crystallization. Moreover, all the local Avrami exponent n(x) possesses a value of about 0

Published
2024
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46. Core–shell structured Co3O4@NiCo2O4 electrodes grown on Ni foam for high-performance supercapacitors.

Author

Sun, Xiaochen and Jian, Zengyun

Subjects
*ENERGY storage, *ENERGY density, *SUPERCAPACITORS, *SUPERCAPACITOR electrodes, *ELECTRODE potential, *ELECTRODES, *FOAM
Abstract

Recently, supercapacitors (SCs) have emerged as one of the most promising energy storage devices, which can be attributed to their exceptional power density, rapid charge–discharge rate, and superior cycling stability. Despite the progress made in the signal metal oxide of SCs, several challenges still need to be addressed, including the poor electrical conductivity, unsatisfactory cyclic stability, and low energy density. It is crucial to develop innovative composite materials with synergistic effects to address these issues. In this study, the cobalt oxide and Co3O4@NiCo2O4 composite were successfully synthesized on Ni foams by a hydrothermal method. Composite electrodes featured by the hierarchical core–shell structures were identified as an effective approach for improving the electrochemical performance of SCs. Noteworthily, the as-fabricated core–shell structures demonstrated excellent specific capacitance of 1514 F g−1 at a current density of 1 A g−1, a stable operating voltage of 0–0.5 V and outstanding cycling stability (with almost no attenuation after 2000 cycles at a charge–discharge current density of 10 A g−1). The enhanced electrochemical behavior can be attributed to the synergistic effect between two electrode active materials and the presence of more electron and ion transport pathways. The as-prepared composite electrodes can be considered as the potential electrode materials for energy storage applications. [ABSTRACT FROM AUTHOR]

Published
2024
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47. A Novel Spinel High-Entropy Oxide (Cr 0.2 Mn 0.2 Co 0.2 Ni 0.2 Zn 0.2) 3 O 4 as Anode Material for Lithium-Ion Batteries.

Author

Jin, Changqing, Wang, Yulong, Dong, Haobin, Wei, Yongxing, Nan, Ruihua, Jian, Zengyun, Yang, Zhong, and Ding, Qingping

Subjects
LITHIUM-ion batteries, NANOPARTICLES, SPINEL, ANODES, COMBUSTION
Abstract

In this study, we synthesized spinel high-entropy oxide (HEO) (Cr0.2Mn0.2Co0.2Ni0.2Zn0.2)3O4 nanoparticles by a simple solution combustion method. These particles were investigated for their performance as anodes in lithium-ion batteries. The reversible capacity is 132 mAh·g−1 after 100 cycles at a current density of 100 mA·g−1, 107 mAh·g−1 after 1000 cycles at a current density of 1 A g−1, and 96 mAh·g−1 rate capacity at a high current density of 2 A g−1. The outstanding cycle stability under high current densities and remarkable rate performance can be attributed to the stable structure originating from the high entropy of the material. [ABSTRACT FROM AUTHOR]

Published
2024
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