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676 results on '"Deng, Yonghong"'

154. Gas Generation Mechanism in Li‐Metal Batteries.

Author

Zhao, Huajun, Wang, Jun, Shao, Huaiyu, Xu, Kang, and Deng, Yonghong

Subjects
CHEMICAL decomposition, MASS spectrometry, HIGH voltages, GASES, PHASE transitions
Abstract

Gas generation induced by parasitic reactions in lithium‐metal batteries (LMB) has been regarded as one of the fundamental barriers to the reversibility of this battery chemistry, which occurs via the complex interplays among electrolytes, cathode, anode, and the decomposition species that travel across the cell. In this work, a novel in situ differential electrochemical mass spectrometry is constructed to differentiate the speciation and source of each gas product generated either during cycling or during storage in the presence of cathode chemistries of varying structure and nickel contents. It unambiguously excludes the trace moisture in electrolyte as the major source of hydrogen and convincingly identifies the layer‐structured NCM cathode material as the source of instability that releases active oxygen from the lattice at high voltages when NCM experiences H2 → H3 phase transition, which in turn reacts with carbonate solvents, producing both CO2 and proton at the cathode side. Such proton in solvated state travels across the cell and becomes the main source for hydrogen generated at the anode side. Mechanisms are proposed to account for these irreversible reactions, and two electrolyte additives based on phosphate structure are adopted to mitigate the gas generation based on the understanding of the above decomposition chemistries. [ABSTRACT FROM AUTHOR]

Published
2022
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155. Preparation of a 24-nor-1,4-dien-3-one triterpene derivative from betulin: a new route to 24-nortriterpene analogues

Author

Deng, Yonghong and Snyder, John K.

Subjects
Chemistry, Organic -- Research, Terpenes -- Physiological aspects, Acids -- Physiological aspects, Ring formation (Chemistry) -- Physiological aspects, Biological sciences, Chemistry
Abstract

Research has been conducted on the 24-nortriterpene derivatives. The route to these derivatives has been developed in preparing the betulinic acid derivatives and the results indicate that the key step in transformation is the A-ring Suarez cleavage.

Published
2002

170. Mechanism Study of Unsaturated Tripropargyl Phosphate as an Efficient Electrolyte Additive Forming Multifunctional Interphases in Lithium Ion and Lithium Metal Batteries

Author

Qian, Yunxian, primary, Kang, Yuanyuan, additional, Hu, Shiguang, additional, Shi, Qiao, additional, Chen, Qun, additional, Tang, Xiwu, additional, Xiao, Yinglin, additional, Zhao, Huajun, additional, Luo, Guangfu, additional, Xu, Kang, additional, and Deng, Yonghong, additional

Published
2020
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183. How electrolyte additives work in Li-ion batteries

Author

Qian, Yunxian, primary, Hu, Shiguang, additional, Zou, Xianshuai, additional, Deng, Zhaohui, additional, Xu, Yuqun, additional, Cao, Zongze, additional, Kang, Yuanyuan, additional, Deng, Yuanfu, additional, Shi, Qiao, additional, Xu, Kang, additional, and Deng, Yonghong, additional

Published
2019
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193. Natural Cocoons Enabling Flexible and Stable Fabric Lithium–Sulfur Full Batteries.

Author

An, Yanan, Luo, Chao, Yao, Dahua, Wen, Shujing, Zheng, Peitao, Chi, Shangsen, Yang, Yu, Chang, Jian, Deng, Yonghong, and Wang, Chaoyang

Abstract

Highlights: A creative cooperative strategy involving silk fibroin/sericin is proposed for stabilizing high-performance flexible Li–S full batteries with a limited Li excess of 90% by simultaneously inhibiting lithium dendrites, adsorbing liquid polysulfides, and anchoring solid lithium sulfides. Such fabric Li–S full batteries offer high volumetric energy density (457.2 Wh L−1), high-capacity retention (99.8% per cycle), and remarkable bending capability (6000 flexing cycles at a small radius of 5 mm). Lithium–sulfur batteries are highly appealing as high-energy power systems and hold great application prospects for flexible and wearable electronics. However, the easy formation of lithium dendrites, shuttle effect of dissolved polysulfides, random deposition of insulating lithium sulfides, and poor mechanical flexibility of both electrodes seriously restrict the utilization of lithium and stabilities of lithium and sulfur for practical applications. Herein, we present a cooperative strategy employing silk fibroin/sericin to stabilize flexible lithium–sulfur full batteries by simultaneously inhibiting lithium dendrites, adsorbing liquid polysulfides, and anchoring solid lithium sulfides. Benefiting from the abundant nitrogen- and oxygen-containing functional groups, the carbonized fibroin fabric serves as a lithiophilic fabric host for stabilizing the lithium anode, while the carbonized fibroin fabric and the extracted sericin are used as sulfiphilic hosts and adhesive binders, respectively, for stabilizing the sulfur cathode. Consequently, the assembled Li–S full battery provided a high areal capacity (5.6 mAh cm−2), limited lithium excess (90%), a high volumetric energy density (457.2 Wh L−1), high-capacity retention (99.8% per cycle), and remarkable bending capability (6000 flexing cycles at a small radius of 5 mm). [ABSTRACT FROM AUTHOR]

Published
2021
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194. Development of a thermal compensator based on PLC for Fanuc CNC system.

Author

Deng, Yonghong, Liu, Jian, and Li, Dong

Subjects
*NUMERICAL control of machine tools, *MACHINE tools, *WORKBENCHES
Abstract

To improve the machining accuracy and stability of CNC machine tools, the lead screw is divided into several segments, and the action law of single section thermal deformation is analyzed, then the thermal deformation model of lead screw base on subsection processing is established. Then the relative relation of thermal deformation of each segment, the cumulative thermal drift of thermal deformation of each segment itself, the total thermal deformation of the free end of lead screw, and the relationship between them are obtained. Then, a segmented thermal compensator based on PLC for CNC system is developed. The thermal error of each segment of the lead screw is detected and compensated separately, and then the thermal error of the segment where the machine tool worktable moves to the different segment of the lead screw is compensated. Tests show that the segmented thermal compensator has achieved good actual compensation effect, so that the positioning error caused by thermal deformation of each shaft can be reduced by more than 50%. [ABSTRACT FROM AUTHOR]

Published
2021
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195. A Four‐Armed Polyacrylic Acid Homopolymer Binder with Enhanced Performance for SiOx/Graphite Anode.

Author

Luo, Chao, Wu, Xiufen, Zhang, Tian, Chi, Shang‐Sen, Liu, Zhengying, Wang, Jun, Wang, Chaoyang, and Deng, Yonghong

Subjects
POLYACRYLIC acid, HYDROGEN bonding
Abstract

The large‐scale application of Si‐based anodes is impeded by their fast capacity decay, which is mainly attributed to the huge volume expansion upon cycling. The employment of functional binders is one efficient method to mitigate this issue. In this work, a four‐armed polyacrylic acid (4A‐PAA) homopolymer is explored as a remarkably effective binder for Si‐based anodes. The 4A‐PAA binder is prepared via an atom transfer radical polymerization, followed by ester hydrolysis. Compared to the conventional linear polyacrylic acid (PAA) binder, the 4A‐PAA not only shows enhanced toughness due to its decreased molecular regularity and intramolecular hydrogen bond but also exhibits increased binding strength because of its multidimensional binding structure. As a result, the SiOx/graphite electrode using the 4A‐PAA retains a capacity retention of 89.1% and a capacity of 558.1 mAh g−1 after 200 cycles at 0.16 A g−1, which are superior to the PAA electrode, corresponding to 80.4% and 469.3 mAh g−1, respectively. The improved performance is attributed to the employment of the 4A‐PAA, which mitigates the volume change of the SiOx/graphite anode. This work not only offers a promising binder for Si‐based anodes but also presents a universal solution for other anodes with high volume expansion during cycling. [ABSTRACT FROM AUTHOR]

Published
2021
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198. Stable Lithium Metal Anodes with a GaOxArtificial Solid Electrolyte Interphase in Damp Air

Author

Han, Bing, Zou, Yucheng, Ke, Ruohong, Li, Tengteng, Zhang, Zhen, Wang, Chaoyang, Gu, Meng, Deng, Yonghong, Yao, Jianquan, and Meng, Hong

Abstract

As a promising high energy density electrode material for rechargeable batteries, lithium (Li) metal is still suffering from air/water instability due to its highly reactive nature. In addition, the Li dendrite issue in Li metal batteries needs to be resolved to ensure the safety of batteries and for wide applications. Herein, we demonstrate that a simple compact GaOxlayer formed using liquid metal (LM) can act as an artificial solid electrolyte interphase to block moisture and oxygen in the air from corroding the lithium metal. Interestingly, GaOxthat covered the electrode effectively inhibits Li dendrite growth in electrochemistry cycling, ensuring the safety of Li metal batteries. The exposed composite Li metal anode (exposed under ambient air with relative humidity (RA) ≈ 75% for 5 h) not only shows a superior stability (symmetrical cell) but also delivers an elevated cycling stability (>500 cycles at 0.5 and 1 C) with a sulfur@C cathode in the full-cell configuration. Our work provides a new pathway for the large-scale applications of the air/water-tolerant Li metal anode in rechargeable batteries.

Published
2021
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200. Engineering optimization approach of nonaqueous electrolyte for sodium ion battery with long cycle life and safety

Author

Che, Haiying, Yang, Xinrong, Yu, Yan, Pan, Chaoliang, Wang, Hong, Deng, Yonghong, Li, Linsen, and Ma, Zi-Feng

Abstract

Electrolyte design strategies are closely related to the capacities, cycle life and safety of sodium–ion batteries. In this study, we aimed to optimize electrolyte with the focus on engineering aspects. The basic physicochemical properties including ionic conductivity, viscosity, wettability and thermochemical stability of the electrolytes using NaPF6as the solute and the mixed solvent with different components of EMC, DMC or DEC in PC or EC were systematically measured. Ah pouch cell with NaNi1/3Fe1/3Mn1/3O2/hard carbon electrodes was used to evaluate the performance of the prepared electrolytes. By using the Inductive Coupled Plasma Emission Spectrometer (ICP), X-ray photoelectron spectroscopy (XPS), Thermogravimetric-differential scanning calorimetry (TG-DSC) and Accelerating Rate Calorimeter (ARC), we show that an optimized electrolyte can effectively promote the formation of a protective interfacial layer on two electrodes, which not only retards parasitic reactions between the electrodes and electrolyte but also suppresses dissolution of metal ions from the cathode. With an optimized electrolyte, a NaNi1/3Fe1/3Mn1/3O2/hard carbon cell can attain 56.16% capacity retention under the low temperature of −40 °C, and can be able to retain 80% capacity retention after more than 2500 cycles while presenting excellent thermal safety.

Published
2021
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