CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Jinqiu Du,Zhiyuan Liu,Zhe Zhu
In this paper, LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NMC811) thin films were prepared by the sol-gel method based on different parameter conditions, and the microstructure and electrochemical properties of the films were compared to obtain the film sample under the best preparation parameters. In order to explain the formation mechanism of cell battery performance based on the NMC811 cathode at the nano scale , electrochemical strain microscopy, conductive atomic force microscopy and Kelvin probe force microscopy are specifically utilized to study the changes of NMC811 thin film in electrochemical deformation, conductivity, and potential distribution under different electrical and thermal fields. The results indicate that the local amplitude, conductivity, and electrical potential of thin film in the scanning region increases with the voltage from 0 V to 3 V and the temperature from 25 °C to 150 °C. However, the electrochemical deformation, conductivity, and potential of the film decrease significantly when the voltage is applied to 4 V or the temperature rises to 200 °C. These results provide visual evidence for the influence of external field on the phase structure change and lithium-ion diffusion behavior of NMC811 thin film.
研究领域:
材料科学
·
电化学
·
纳米科技
·
固体离子学
·
能源材料
✓ 已验证
DOI
高影响因子
Small
·
2024
·Vol. 20
·期 34
·2312059
·
IF 13
Lu Wei,Hongyuan Wu,Songtao Liu,Yuyu Zhou,Xin Guo
Realizing high-performance thick electrodes is considered as a practical strategy to promote the energy density of lithium-ion batteries. However, establishing effective transport pathways for both lithium-ions and electrons in a thick electrode is very challenging. This study develops a hierarchical conductive network structure for constructing high-performance NMC811 (LiNi 0.8 Mn 0.1 Co 0.1 O 2 ) cathode toward stable cycling at high areal mass loadings. The hierarchical conductive networks are composed of a Li + /e − mixed conducting interface (lithium polyacrylate/hydroxyl-functionalized multiwalled carbon nanotubes) on NMC811 particles, and a segregated network of single-walled carbon nanotubes in the electrode, without any additional binders or carbon black. Such strategy endows the NMC811 cathode (up to 250 µm and 50 mg cm −2 ) with low porosity/tortuosity, ultrahigh Li + /e - conductivities and excellent mechanical property at low carbon nanotube content (1.8 wt%). It significantly improves the electrochemical reaction homogeneity along the electrode depth, meanwhile effectively inhibits the side reactions at the electrode/electrolyte interface and cracks in the NMC particles during cycling. This work emphasizes the crucial role of the electronic/ionic cooperative transportation in the performance deterioration of thick cathodes, and provide guidance for architecture optimization and performance improvement of thick electrodes toward practical applications, not just for the NMC811 cathode.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ACS Applied Energy Materials
·
2019
·
IF 0
Qingyu Dong,Feng Guo,Zhenjie Cheng,Yayun Mao,Rong Huang,Fangsen Li,Houcai Dong,Qingyong Zhang,Wei Li,Hui Chen,Zhaojun Luo,Yanbin Shen,Xiaodong Wu,Liwei Chen
Ni-rich layered oxides (LiNixMnyCozO2, x ≥ 0.6, x + y + z = 1) are promising positive electrode materials for high energy density lithium-ion batteries thanks to their high specific capacity. However, large-scale application of Ni-rich layered oxides is hindered by its poor structural and interfacial stability, especially during cycling at a high cutoff potential (i.e., ≥ 4.3 V, versus Li+/Li). Herein, we demonstrate that lithium difluoro(oxalato)borate (LiDFOB) as a film-forming additive plays a dual role on the electrode|electrolyte interphase formation in a LiNi0.83Mn0.05Co0.12O2||graphite cell, meaning that it can not only be reduced on the graphite negative electrode but also oxidized on the nickel-rich oxide LiNi0.83Mn0.05Co0.12O2 positive electrode cycled at a high cutoff potential (4.4 V, versus Li+/Li) prior to typical carbonate-based electrolyte constituents. As a result, the addition of 1.5 wt % LiDFOB greatly reduces the polarization and improves the cycling stability of the LiNi0.83Mn0.05Co0.12O2||graphite cell, which shows a high discharge capacity of 198 mA h g–1, and more than 83.1% of the initial capacity was retained after 200 cycles at C/3 (the capacity retention obtained at the same cycling condition is only 59.9% for the cell without LiDFOB additive). Furthermore, the employ of LiDFOB additive also significantly suppresses the self-discharge of the LiNi0.83Mn0.05Co0.12O2||Li cell during high-temperature and long-term room-temperature storage at 4.4 V. These electrochemical performance enhancements could be attributed to the participation of LiDFOB in forming a stable and Li+ transfer favorable protective layer that is rich in inorganic boron, fluorine, and carbonate compounds on both the surface of the LiNi0.83Mn0.05Co0.12O2 positive electrode and the graphite negative electrode, thus suppressing the electrolyte decomposition on the positive electrode and negative electrode surfaces and decreasing the dissolution of transition-metal ions from the positive electrode bulk.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Qingshuai Xu,Xuejun Lai,Gaige Zhang,Tan Li,Yongcai Qiu
Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is widely employed in lithium metal batteries (LMB) owing to its capacity for efficiently mitigating the growth of lithium dendrites and enhancing the interface stability of lithium metal anodes. Unfortunately, LiTFSI frequently causes severe aluminum (Al) corrosion and leads to LMB failure. To address this issue, we conducted solvation structure design in the electrolyte using co-solvents such as 1,2-diethoxyethane, fluoroethylene carbonate and adiponitrile. Both experimental and computational evidences demonstrate that the co-solvents can regulate the solvation structure of electrolyte and promote the formation of more anion-rich internal solvation shells, ultimately enhancing the interfacial stability of Li anode and Al collector. When paired with high-loading LiFePO 4 cathode, the full cell exhibits a long-term lifespan (1000 cycles) and outstanding capacity retention (86.4 %). Even the full cell with stringent conditions of NMC811 (∼4.0 mAh cm −2 ), 50 μm thin Li (N/P = 2.5) and the optimized electrolyte still enables to output over 110 cycles and 80.0 % capacity retention. This work provides an efficacious and innovative strategy to stabilize Li metal anode and Al current collector through solvation structure regulation.
研究领域:
材料科学
·
电化学
·
储能技术
·
电池技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）