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117 results on '"Hou, Junxian"'

43. Thermal Runaway of Lithium‐Ion Batteries Employing Flame‐Retardant Fluorinated Electrolytes.

Author

Hou, Junxian, Wang, Li, Feng, Xuning, Terada, Junpei, Lu, Languang, Yamazaki, Shigeaki, Su, Anyu, Kuwajima, Yoshiko, Chen, Yongjiang, Hidaka, Tomoya, He, Xiangming, Wang, Hewu, and Ouyang, Minggao

Subjects
LITHIUM-ion batteries, FIREPROOFING agents, ELECTROLYTES, THERMAL batteries, ENTHALPY
Abstract

Fluorinated electrolytes possess good antioxidant capacity that provides high compatibility to high‐voltage cathode and flame retardance; thus, they are considered as a promising solution for advanced lithium‐ion batteries carrying both high‐energy density and high safety. Moreover, the fluorinated electrolytes are widely used to form stable electrolyte interphase, due to their chemical reactivity with lithiated graphite or lithium. However, the influence of this reactivity on the thermal safety of batteries is seldom discussed. Herein, we demonstrate that the flame‐retardant fluorinated electrolytes help to reduce the flammability, while the lithium‐ion batteries with flame‐retardant fluorinated electrolytes still undergo thermal runaway and disclose their different thermal runaway pathway from that of battery with conventional electrolyte. The reduction in fluorinated components (e.g., LiPF6 and fluoroethylene carbonate (FEC)) by fully lithiated graphite accounts for a significant heat release during battery thermal runaway. The 13% of total heat is sufficient to trigger the chain reactions during battery thermal runaway. This study deepens the understanding of the thermal runaway mechanism of lithium‐ion batteries employing flame‐retardant fluorinated electrolytes, providing guidance on the concept of electrolyte design for safer lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

Published
2023
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44. Hollow FeOOH nanorods decorated with MnO2 nanosheets as electrode materials for high-performance asymmetric supercapacitors.

Author

Tong, Lin, Wu, Chunxia, Hou, Junxian, Yan, Jiayuan, Zhang, Xiaoliang, Mu, Jingbo, Wang, Zehu, Wang, Yanming, Che, Hongwei, and Zhang, Zhixiao

Subjects
SUPERCAPACITOR electrodes, NANORODS, NANOSTRUCTURED materials, SUPERCAPACITORS, ENERGY density, ELECTROCHEMICAL electrodes
Abstract

Nano core–shell structured materials have different or better properties than single components, which can realize the design and optimization of nanoscale particle structure and properties. Additionally, hollow core–shell materials have the advantages of large specific surface area, abundant active sites, low density, short mass transfer path, and wide cavity structure, which are widely used in the fields of electrochemistry, biomedicine, and environmental protection. Herein, hollow core–shell FeOOH@MnO2 nanorod composites were prepared by easiest hydrothermal method. Due to the synergy and versatility between the hollow FeOOH nanorods core and the MnO2 nanosheets shell, the FeOOH@MnO2 composite exhibits outstanding electrochemical characteristic as an electrode material with specific capacitance of 924 F g−1 at 1 A g−1, admirable rate capability (capacitance retention of 75.9% from 1 to 10 A g−1), and remarkable cycling stability (91.2% of initial capacity retained after 5000 charge/discharge cycles). Notably, the assembled FeOOH@MnO2//activated carbon (AC) asymmetric supercapacitor facility possessed an energy density of 53.4 Wh kg−1 and a power density of 722 W kg−1, indicating that the hollow core–shell FeOOH@MnO2 nanorod nanocomposite is a viable electrode material that can be used in supercapacitors. [ABSTRACT FROM AUTHOR]

Published
2022
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49. Modified capacitor voltage balancing sorting algorithm for modular multilevel converter.

Author

Zhang, Jie, Liu, Jun, Liu, Jiayu, Fang, Wanliang, Hou, Junxian, and Dong, Yifeng

Subjects
ELECTRIC current converters, CAPACITORS, HIGH-voltage direct current transmission, POWER electronics, ELECTRIC power distribution grids
Abstract

The modular multilevel converter (MMC) with large-scale sub-modules has the advantage of simpler modulation, lower switching frequency, and lower harmonic component, thus would be very promising in voltage source converter (VSC)–high voltage direct current transmission systems. Conventional capacitor voltage balancing algorithm suffers from insufficient grouping and sorting techniques. Therefore, it might result in excessive computation and high switching frequency of power electronic devices. To address the problem, a modified capacitor voltage balancing sorting algorithm is proposed in this paper. The proposed algorithm could avoid sorting all the module capacitor voltages by selecting only a certain number of the largest or smallest module capacitor voltages, and thus reduces time complexity greatly without losing control precision. Furthermore, the proposed algorithm focuses on the sub-modules whose capacitor voltage exceeds the limits, while the switching states of the other sub-modules are maintained to some degrees by employing the maintaining factor. Therefore, the switching frequency of the power electronic devices is further reduced. The performance of the proposed algorithm is evaluated through a time-domain MMC–HVDC simulation in PSCAD/EMTDC. Results show that the proposed algorithm is able to balance the module voltage with lower computation and reduce the switching frequency of power devices significantly, without noticeably increasing the capacitor voltage ripples. [ABSTRACT FROM AUTHOR]

Published
2019
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50. Control of photovoltaic power integration based on multi-terminal VSC–HVDC system.

Author

Wang, Lei, Wu, Xiaolong, Hou, Junxian, and Wang, Tiezhu

Subjects
PHOTOVOLTAIC power generation, HIGH-voltage direct current converters, ELECTRIC power distribution grids, DIRECT current generators, SHORT circuits
Abstract

In order to solve the problem of long-distance transmission of large-scale photovoltaic power stations, a multi-terminal voltage source converter-based high-voltage direct current (VSC–HVDC) system based on a DC voltage-active power-AC voltage control strategy, which is connected with photovoltaic power stations, is designed in this study. In order to verify the feasibility of the method, a model of a five-terminal parallel system is established by MATLAB/Simulink, which includes two photovoltaic power stations and a passive network. A series of simulations are carried out based on the model. The results show that the active power of the system can be automatically balanced when the output power of photovoltaic power stations changes. When the three-phase short-circuit fault occurs in power grid, the photovoltaic power stations can still run in a stable state and have better fault ride-through ability. [ABSTRACT FROM AUTHOR]

Published
2019
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