JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Zecheng Yang,Liluo Shi,Hao Wang,Jianzhen Xiong,Xuena Xu,Limei Sun,Jiangmin Jiang,Quanchao Zhuang,Yaxin Chen,Zhicheng Ju
Carbon nanosheets (CNS) have garnered significant interest as anode materials for potassium-ion batteries (PIBs) due to the excellent potassium storage kinetics and rate performance. Moreover, tuning the thickness of CNS can enhance the potassium storage performance by exposing abundant surface active sites and shortening the K + migration path. Herein, crystallization-induced thickness tuning of carbon nanosheets in polyvinyl pyrrolidone-potassium chloride (PVP-KCl) solution is reported to enhance the fast potassium storage. PVP with varying molecular weights is employed to induce the crystallization behavior of KCl, leading to the formation of KCl grains with controllable sizes. Concurrently, these KCl grains act as hard templates for dispersing the PVP molecules to fabricate carbon nanosheets on the surface during annealing. PVP with high molecular weight is beneficial for hindering ion migration to reduce crystal sizes, which can decrease the thickness of carbon nanosheets. The ultrathin structure exposes abundant potassium storage sites, endowing CNS with high reversible capacity (359.0 mAh/g at 100 mA/g). The reduction in the migration path of K + ions facilitate rapid ion and electron transport kinetics, resulting in rate performance with a capacity of 181.9 mAh/g at 1 A/g. Our work extends the application of the crystallization-induced strategy for controllable designing carbon nanosheets, and puts forward some conceptions on improving the potassium storage performance of carbon anode materials.
研究领域:
材料科学
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电化学
·
纳米能源
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储能技术
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碳材料
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电池材料
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jingsheng Xu,Zhiyuan Wang,Runguo Zheng,Hongyu Sun,Yanguo Liu,Junhua You
Ni-rich cathodes especially with Ni content over 90 % are promising next-generation cathode materials for advanced high energy lithium − ion batteries. However, in comparison with Ni ≤ 80 % Ni-rich cathodes, these ultrahigh Ni-rich materials face more severe challenges in terms of harmful H2 − H3 phase transformations and structural degradation during cycling. Herein, we present a robust surface structure composted of defect-rich disordered structures and LiF/Li 2 SiO 3 coating for stabilizing the ultrahigh Ni-rich cathode LiNi 0.96 Co 0.03 Mn 0.01 O 2 (NCM96) by modification with (NH 4 ) 2 SiF 6 . The surface disordered structures including Li/TM mixing, spinel, and rock salt structure play a crucial role in inhibiting the irreversible H2-H3 phase transition and reducing lattice volume changes by lattice coherence effect. Moreover, the disordered surface in collaboration with the co-coating restrains the rapid growth of surface rock salt phase into the bulk, enhancing structural stability. The modified sample NSF-0.5 delivers a capacity of 238 mAh/g at 0.1C and maintains a capacity retention of 88.5 % at 0.5C after 100 cycles in half cell as well as 82.3 % at 1C after 300 cycles in full cell, significantly superior to the NCM96. The findings provide a simple and cost-effective surface modification strategy to enhance the structural stability and electrochemical performance of ultrahigh nickel cathodes for high-energy density LIBs.
研究领域:
材料科学
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电化学
·
能源存储
·
锂离子电池
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固态化学
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表面工程
·
电池材料
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 22
·11930-11939
·
IF 7.443
Shaojie Han,Yonggao Xia,Zhen Wei,Bao Qiu,Lingchao Pan,Qingwen Gu,Zhaoping Liu,Zhiyong Guo
The Li-rich layered oxides are attractive electrode materials due to their high reversible specific capacity (>250 mA h g−1); however, the origin of their abnormal capacity is still ambiguous. In order to elucidate this curious anomaly, we compare the lattice oxygen oxidation states among the Li-rich layered oxide Li1.14Ni0.136Co0.136Mn0.544O2, Li2MnO3 and LiNi0.5Co0.2Mn0.3O2, the two components in Li-rich layered oxides, and the most common layered oxide LiCoO2 before and after initial charge–discharge. For simplicity, we employ chemical treatments of NO2BF4 and LiI acetonitrile solutions to simulate the electrochemical delithiation and lithiation processes. X-ray photoelectron spectroscopy (XPS) studies reveal that part of lattice oxygen in Li1.14Ni0.136Co0.136Mn0.544O2 and Li2MnO3 undergoes a reversible redox process (possibly O2− ↔ O22−), while this does not occur in LiNi0.5Co0.2Mn0.3O2 and LiCoO2. This indicates that the extra capacity of Li-rich layered oxides can be attributed to the reversible redox processes of oxygen in the Li2MnO3 component. Thermogravimetric analysis (TGA) further suggests that the formed O22− species in the delithiated Li1.14Ni0.136Co0.136Mn0.544O2 can decompose into O2 at about 210 °C. This phenomenon demonstrates a competitive relationship between extra capacity and thermal stability, which presents a big challenge for the practical applications of these materials.
研究领域:
材料科学
·
电化学
·
储能
·
电池材料
·
固态化学
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·Vol. 8
·期 12
·12735-12740
·
IF 1.5
Binbin Zhang,Yuan Zhou,Xiang Li,Xiufeng Ren,Hongen Nian,Yue Shen,Qiang Yun
FTIR (Fourier transformed infrared) spectra have been collected and analyzed for solutions of lithium tetrafluoroborate in propylene carbonate (PC). It has been shown that the carbonyl stretch, symmetric ring deformation stretch and ring deformation stretch bands for PC is very sensitive to the interaction between Li + and the solvent molecule. Their half-peak breadth increases and bands split with the addition of LiBF 4 , indicating that a strong interaction exists between Li + and PC molecule mainly through the oxygen group of C=O and ring position of PC.
研究领域:
物理化学
·
光谱学
·
电解质溶液
·
电池材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）