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215. A nano-truncated Ni/La doped manganese spinel material for high rate performance and long cycle life lithium-ion batteries.

Author

Li, Meng, Li, Yan, Guo, Yujiao, Guo, Junming, Xiang, Mingwu, Bai, Wei, Liu, Xiaofang, and Bai, Hongli

Subjects
LITHIUM-ion batteries, SPINEL, JAHN-Teller effect, MANGANESE, SPINEL group, TRANSITION metal oxides
Abstract

The spinel LiMn2O4 cathode material provides high energy and low cost, but suffers from poor cycling performance and rate capability owing to Mn dissolution and Jahn–Teller distortion. Herein, our design concept is to combine Ni–La co-doping with the nanoscale truncated octahedron to solve this issue; namely, a novel nano-LiNi0.08La0.01Mn1.91O4 cathode material with a truncated octahedron is fabricated for the first time through a facile and quick solution combustion approach. It is found that the Ni–La dual doping promotes the {111} surface growth in spinel LiMn2O4, which endows the nano-LiNi0.08La0.01Mn1.91O4 sample with the majority of {111} facets for minimal Mn dissolution and a few truncated {100} facets for rapid Li+ ion migration channels, as well as the nanoscale particles facilitating decreased electronic and ionic diffusion paths. In addition, the introduction of Ni–La elements can strengthen the crystal structure stability and restrain the Jahn–Teller effect effectively. Consequently, the nano-LiNi0.08La0.01Mn1.91O4 presents excellent electrochemical properties with high first discharge capacities of 114.9 and 100.4 mA h g−1 at 1C and 5C, respectively. Importantly, at the current rate up to 10C, a capacity retention ratio of 89.0% is acquired after an ultra-long 1000 cycles. The CV and EIS measures manifest that the Ni–La dual doping improves the Li+ ion transport rate and weakens the reaction barrier in the nano-LiNi0.08La0.01Mn1.91O4. This research will be a promising candidate for developing long cycle power lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Published
2022
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222. Light absorption properties of elemental carbon (EC) and water-soluble brown carbon (WS–BrC) in the Kathmandu Valley, Nepal: A 5-year study

Author

Chen, Pengfei, primary, Kang, Shichang, additional, Tripathee, Lekhendra, additional, Ram, Kirpa, additional, Rupakheti, Maheswar, additional, Panday, Arnico K., additional, Zhang, Qianggong, additional, Guo, Junming, additional, Wang, Xiaoxiang, additional, Pu, Tao, additional, and Li, Chaoliu, additional

Published
2020
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237. Dissolved organic carbon in Alaskan Arctic snow: concentrations, light-absorption properties, and bioavailability

Author

Zhang, Yulan, primary, Kang, Shichang, additional, Gao, Tanguang, additional, Sprenger, Michael, additional, Dou, Tingfeng, additional, Han, Wei, additional, Zhang, Qi, additional, Sun, Shiwei, additional, Du, Wentao, additional, Chen, Pengfei, additional, Guo, Junming, additional, Cui, Xiaoqing, additional, and Sillanpää, Mika, additional

Published
2020
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242. Stimulative formation of truncated octahedral LiMn2O4 by Cr and Al co-doping for use in durable cycling Li-ion batteries.

Author

Liang, Qimei, Wang, Zilin, Bai, Wei, Guo, Junming, Xiang, Mingwu, Liu, Xiaofang, and Bai, Hongli

Subjects
LITHIUM-ion batteries, ELECTRON configuration, STRUCTURAL stability, SINGLE crystals, FAST ions
Abstract

The rational design of the unique morphology of particles has been considered as the key to improving the structural stability of spinel LiMn2O4 cathode materials for Li-ion batteries. Herein, a facile solid-state combustion process, combined with a Cr and Al co-doping approach, is proposed to prepare various LiCr0.01AlxMn1.99−xO4 (x ≤ 0.10) cathode materials with a good crystallinity. Cr and Al co-doping facilitates the formation of a single crystal truncated octahedral morphology. This endows the as-prepared LiCr0.01AlxMn1.99−xO4 with abundant {111} planes for Mn dissolution reduction and a few {100} and {110} planes for Li+ ion fast diffusion channels. Moreover, the introduction of Cr and Al elements with a stable electronic configuration further boosts the structural stability of the spinel LiMn2O4 owing to the relatively robust Al–O and Cr–O bonds compared with the Mn–O bond. Owing to these advantages, the optimal LiCr0.01Al0.05Mn1.94O4 delivers a good electrochemical performance with a high first discharge capacity of 118.5 mA h g−1 and a capacity retention of 70.8% after 1000 cycles at 1 C. Even at relatively high current rates of 15 and 20 C, a durable and prolonged cycling performance of up to 3000 cycles can be achieved. In addition, a high-temperature capacity retention of 72.1% is also maintained after 200 cycles at 5 C under 55 °C. This work provides potential candidates for developing long-life Li-ion batteries with a simultaneously high capacity. [ABSTRACT FROM AUTHOR]

Published
2021
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247. Linking atmospheric pollution to cryospheric change in the Third Pole region : current progress and future prospects

Author

Kang, Shichang, Zhang, Qianggong, Qian, Yun, Ji, Zhenming, Li, Chaoliu, Cong, Zhiyuan, Zhang, Yulan, Guo, Junming, Du, Wentao, Huang, Jie, You, Qinglong, Panday, Arnico K., Rupakheti, Maheswar, Chen, Deliang, Gustafsson, Örjan, Thiemens, Mark H., Qin, Dahe, Kang, Shichang, Zhang, Qianggong, Qian, Yun, Ji, Zhenming, Li, Chaoliu, Cong, Zhiyuan, Zhang, Yulan, Guo, Junming, Du, Wentao, Huang, Jie, You, Qinglong, Panday, Arnico K., Rupakheti, Maheswar, Chen, Deliang, Gustafsson, Örjan, Thiemens, Mark H., and Qin, Dahe

Abstract

The Tibetan Plateau and its surroundings are known as the Third Pole (TP). This region is noted for its high rates of glacier melt and the associated hydrological shifts that affect water supplies in Asia. Atmospheric pollutants contribute to climatic and cryospheric changes through their effects on solar radiation and the albedos of snow and ice surfaces; moreover, the behavior and fates within the cryosphere and environmental impacts of environmental pollutants are topics of increasing concern. In this review, we introduce a coordinated monitoring and research framework and network to link atmospheric pollution and cryospheric changes (APCC) within the TP region. We then provide an up-to-date summary of progress and achievements related to the APCC research framework, including aspects of atmospheric pollution's composition and concentration, spatial and temporal variations, trans-boundary transport pathways and mechanisms, and effects on the warming of atmosphere and changing in Indian monsoon, as well as melting of glacier and snow cover. We highlight that exogenous air pollutants can enter into the TP's environments and cause great impacts on regional climatic and environmental changes. At last, we propose future research priorities and map out an extended program at the global scale. The ongoing monitoring activities and research facilitate comprehensive studies of atmosphere-cryosphere interactions, represent one of China's key research expeditions to the TP and the polar regions and contribute to the global perspective of earth system science.

Published
2019
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248. High-capacity and superior behavior of the Ni–Cu co-doped spinel LiMn2O4 cathodes rapidly prepared via microwave-induced solution flameless combustion.

Author

Su, Changwei, Chen, Ruifang, Sa, Zhaoyao, Li, Hong, Xiang, Mingwu, Guo, Junming, Bai, Wei, and Liu, Xiaofang

Subjects
SPINEL, SELF-propagating high-temperature synthesis, CATHODES, COMBUSTION, LATTICE constants, CHEMICAL stability, JAHN-Teller effect, SPINEL group
Abstract

A simple and rapid microwave-induced solution flameless combustion method to prepare high-capacity Ni–Cu co-doped spinel LiMn2O4 is provided in this work. Ni–Cu co-doping effectively reduces the lattice parameters and Jahn–Teller effect of the spinel LiMn2O4 to obtain a more stable crystal structure. The microscopic morphological characteristics clarify that the growth and development of grains is significantly controlled by microwave treatment and Ni–Cu co-doping. The optimized LMNCO-0.050 electrode exhibits a higher initial discharge capacity of 128.1 mA h g−1 than the un-doped LMO electrode of 120.6 mA h g−1 at 1 C and room temperature. In particular, the LMNCO-0.050 electrode achieves high initial discharge specific capacities of 111.3 and 106.8 mA h g−1 at high rates of 5 C and 10 C, corresponding to excellent retention rates of 70.89% and 77.43% after 1000 cycles. Moreover, the excellent retention of 41.89% of the LMNCO-0.050 electrode after 1000 ultra-long cycles at 55 °C and 1 C can be attributed to the improved structural stability of the LiMn2O4 by Ni–Cu co-doping. [ABSTRACT FROM AUTHOR]

Published
2021
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