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111 results on '"Peng, Gongchang"'

35. 7‐Hydroxycoumarin as a Novel Film‐Forming Additive for LiNi0.5Mn1.5O4 Cathode at Elevated Temperature.

Author

Shang, Huimin, Jiang, Jinjin, Zhang, Huan, Niu, Wenchao, Qiao, Yingjun, Zhou, Hanxiao, Li, Tianhui, Qu, Meizhen, Peng, Gongchang, and Xie, Zhengwei

Subjects
HIGH temperatures, ADDITIVES, NEGATIVE electrode, TRANSITION metals, THIN films
Abstract

A novel additive, 7‐hydroxycoumarin (7‐HC), is employed to construct a stable interface film on the LiNi0.5Mn1.5O4 cathode to improve the cyclic stability of Li/LiNi0.5Mn1.5O4 cells at elevated temperature (ca. 55 °C). In the 0.01 wt% 7‐hydroxycoumarin‐containing electrolyte, the capacity retention of Li/LiNi0.5Mn1.5O4 cell increases from 78.15 % to 95.64 % at elevated temperature after 100 cycles at 1 C rate. Through theoretical calculations and ex‐situ analysis, it suggests that 7‐HC is susceptible to oxidation than other components of the electrolyte to form a thin and stable film on the surface of LiNi0.5Mn1.5O4 cathode. The thin and stable film can effectively reduce the interface oxidation reaction and the "cross‐talk" between the positive electrode and negative electrode and effectively inhibit the structural changes of LiNi0.5Mn1.5O4 caused by dissolved transition metals in subsequent cycles, thereby improving the cyclic stability of the cell at elevated temperature. [ABSTRACT FROM AUTHOR]

Published
2020
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36. In SituSurface Reaction for the Preparation of High-Performance Li-Rich Mn-Based Cathode Materials with Integrated Surface Functionalization

Author

Su, Zihao, Guo, Zhihao, Xie, Haoyu, Qu, Meizhen, Peng, Gongchang, and Wang, Hao

Abstract

Li-rich Mn-based cathode materials (LLOs) are often faced with problems such as low initial Coulombic efficiency (ICE), limited rate performance, voltage decay, and structural instability. Addressing these problems with a single approach is challenging. To overcome these limitations, we developed an LLO with surface functionalization using a simple fabrication method. This two-step process involved a liquid-stage NaBF4treatment followed by an in situchemical reaction during sintering. This reaction led to the creation of oxygen vacancies (OV), spinel structures, and doping with Na at the Li site, B at the tetrahedral interstitial spaces of O in both the transition-metal (TM) layer and Li layers as well as the octahedral interstices in the TM layer, and F at the O site. We have carried out a thorough study and employed density functional theory calculations to reveal the hidden mechanisms. The treatment not only increases the electrical conductivity but also changes the oxygen charge environment and inhibits lattice oxygen activity. Surprisingly, the B–O bond is so strong that it prevents the migration of TM within the tetrahedral interstitial spaces of O in both the TM and Li layers, hence stabilizing its structure. This bonding interaction strengthens the transition of the TM 3d and O 2p states to lower energy levels, thus causing an increase in the redox potentials. Hence, a rise in the operating voltage occurs. Of special importance, this therapy dramatically increases the ICE to 90.29% and keeps a specified capacity of 203.3 mAh/g after 100 cycles at 1C, which is an excellent capacity retention of 89.94%. This study introduces ideas and methods to tackle the challenges associated with LLOs in batteries. It also provides compelling evidence for the development of high-energy-density Li-ion batteries.

Published
2024
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37. The Synergetic Effect of Inorganic and Organic Compounds Hydrolyzed by Tetrabutyl Titanate on Improving Dispersion and Electrochemical Performance of Li4Ti5O12 Anode Material.

Author

Zhang, Yanhua, Fan, Weifeng, Li, Xuan, Qiao, Yingjun, Hu, Yuxin, Li, Wanpeng, Qu, Meizhen, Peng, Gongchang, and Xie, Zhengwei

Subjects
TITANATES, INORGANIC compounds, PARTICLE size distribution, X-ray photoelectron spectroscopy, ORGANIC compounds, DISPERSION (Chemistry), AGGLOMERATION (Materials)
Abstract

Spinel Li4Ti5O12 (LTO) with small particle size has the problem of easy agglomeration, which seriously worsens electrochemical performance but hasn't been yet attracted enough attention. This is one of the biggest challenges in the practical application of LTO. Herein, LTO is modified with tetrabutyl titanate (TBT) to generate inorganic‐organic wrapped LTO anode under simple hydrolysis process. The X‐ray diffraction, fourier transformation infrared spectrum, scanning electron microscopy, transmission electron microscopy and X‐ray photoelectron spectroscopy results show the existence of modifying layer, which not only could promote dispersion, but also improve the electrochemical performance. The LTO modified with 0.5 wt.% TBT displays good dispersion with homogeneous particle size distribution and stable viscosity. Moreover, it exhibits excellent cycling properties over 200 cycles at 5 C (153.4 mAh g−1). These results are assigned to the synergetic effect of the inorganic and organic modifying layer, which could be beneficial to the dispersion and electrochemical performance. [ABSTRACT FROM AUTHOR]

Published
2020
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38. Surface Modification of Li1.144Ni0.136Co0.136Mn0.544O2 by Hybrid Protection Layer with Enhanced Rate Capability.

Author

Liao, Yingling, Li, Jianbin, Deng, Bangwei, Wang, Hao, Chen, Tao, Li, Xuan, Qu, Meizhen, Li, Xiang, and Peng, Gongchang

Subjects
CHARGE transfer, LITHIUM cell electrodes, GRAPHITIZATION, CATHODES
Abstract

Overlithiated oxide (OLO) materials have received great attention because of their higher recharge capacity (>250 mA h g−1) than that of commercial Li‐ion cathode materials. However, they still have some problems such as poor cyclic stability and rate capability. In this study, La(PO3)3 is coated on Li1.144Ni0.136Co0.136Mn0.544O2 by the dry coating method. The results indicate that 1.0 wt% La(PO3)3–coated Li1.144Ni0.136Co0.136Mn0.544O2 delivers a remarkably high rate capability, with a discharge capacity of 163 mA h g−1 even at 5 C, and an excellent cycling performance of 193 mA h g−1 after cycling 100 times at 1 C. The enhanced electrochemical performance comes from the formation of a hybrid protection layer mainly containing Li, La, P, and O (LLPO), which uses residual alkali compounds, LiOH and Li2CO3, as the lithium source and reacts with La(PO3)3. LLPO can not only protect the Li‐rich cathodes from contacting the electrolyte directly, but also reduce the charge transfer resistance. More importantly, it can serve as a Li+ conductor, which is beneficial for elevation of the rate capability. [ABSTRACT FROM AUTHOR]

Published
2020
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42. Review of Electrolyte Additives for Ternary Cathode Lithium-ion Battery

Author

Peng Gongchang, Sun Daming, Chen Tao, Deng Bangwei, Qu Meizhen, Wan Qi, Li Xuan, and Wang Hao

Subjects
Chemistry, 02 engineering and technology, General Chemistry, Electrolyte, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Lithium-ion battery, Cathode, 0104 chemical sciences, law.invention, Chemical engineering, law, 0210 nano-technology, Ternary operation
Published
2018

49. Facile Fabrication of Ethoxy-Functional Polysiloxane Wrapped LiNi0.6Co0.2Mn0.2O2Cathode with Improved Cycling Performance for Rechargeable Li-Ion Battery

Author

Wang, Hao, Ge, Wujie, Li, Wen, Wang, Feng, Liu, Wenjing, Qu, Mei-Zhen, and Peng, Gongchang

Abstract

Dealing with the water molecule on the surface of LiNi0.6Co0.2Mn0.2O2(NCM) cathode and hydrogen fluoride in the electrolyte is one of the most difficult challenges in Li-ion battery research. In this paper, the surface polymerization of tetraethyl orthosilicate (TEOS) on NCM to generate ethoxy-functional polysiloxane (EPS) wrapped NCM (E-NCM) cathode under mild conditions and without any additions is utilized to solve this intractable problem. The differential scanning calorimetry, transmission electron microscopy, and X-ray photoelectron spectroscopy results show that the formed amorphous coating can provide a protective shell to improve the NCM thermal stability, suppress the thickening of the solid electrolyte interphase (SEI) layer, and scavenge HF in the electrolyte. The E-NCM composite with 2 mol % EPS delivers a high discharge capacity retention of 84.9% after 100 cycles at a 1 C discharge rate in the 2.8–4.3 V potential range at 55 °C. Moreover, electrochemical impedance spectroscopy measurements reveal that the EPS coating could alleviate the impedance rise during cycling especially at an elevated temperature. Therefore, the fabricated E-NCM cathode with long-term cycling and thermal stability is a promising candidate for use in a high-energy Li-ion battery.

Published
2016
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50. Effect of mesoporous carbon containing binary conductive additives in lithium ion batteries on the electrochemical performance of the LiCoO2 composite cathodes

Author

Zhang, Qingtang, Peng, Gongchang, Wang, Guoping, Qu, Meizhen, and Yu, Zuo Long

Subjects
*BATTERY additives, *ELECTRIC conductivity, *CATHODES, *LITHIUM-ion batteries, *ELECTROCHEMISTRY, *PERFORMANCE evaluation, *CARBON, *POROSITY, *METALLIC composites
Abstract

Abstract: Binary conductive additives (BCA), formed by sonication of mesoporous carbon (MC) and acetylene black (AB), were used as conductive additives to improve the electrochemical performance of a LiCoO2 composite cathode. The electrochemical performance of the LiCoO2 composite cathode dispersed with BCA was investigated. The results showed that the electrochemical performance (including the discharge capacity, the discharge voltage and the total internal resistance) of a BCA loaded LiCoO2 composite cathode was better than that of a cathode loaded with AB. The possible mechanism is that the MC in BCA can adsorb and retain electrolyte solution, which allows an intimate contact between the lithium ions and the cathode active material LiCoO2 due to its large mesopore specific surface area. A simplified model was also proposed. [Copyright &y& Elsevier]

Published
2009
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