ACS Applied Nano Materials
·
2022
·
IF 6.14
Dongjia Li,Haijun Chen,Xinyi Dai,Fuzhong Wu,Shuie Li,Yi Mai
LiNi0.5Mn1.5O4 (LNMO) has broad application prospects due to its high discharge platform and low cost. However, the side reactions of the electrolyte during high-temperature and high-voltage cycling severely limit its commercial development. In this study, PrF3 nanocoatings were constructed by wet chemistry to stabilize the surface of LNMO electrodes to solve such problems. The electrochemical test results show that the PrF3 nanocoating can effectively improve the electrochemical performance of the LNMO electrode, especially at high temperature. In the voltage range of 3.5–4.9 V, the 1 wt % PrF3-coated electrode exhibited a capacity retention of 91.4% after 100 cycles at a rate of 0.2C and 55 °C, while the pristine LNMO electrode could not release its capacity after 91 cycles. At a rate of 10C, the discharge capacity of pristine LNMO was only 48.2 mAh g–1, while that of LNMO-PF1 was 88.9 mAh g–1. The characterization of the samples before and after coating further indicates that the PrF3 nanocoating can stabilize the LNMO electrode surface, inhibit its side reactions with the electrolyte, enhance the structural stability, and improve the lithium ion diffusion kinetics. Our study provides an effective way to stabilize the energy density and cycling performance of LNMO at high temperature and high voltage and provides an idea for the protection strategy of high-energy-density lithium batteries working at high voltage.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2016
·
IF 3.014
Shengjie Liu,Hao Wu,Ling Huang,Mingwu Xiang,Heng Liu,Yun Zhang
Ni-rich ternary layered oxides , (LiNi x [M] 1−x O 2 , x ≥ 0.5, M = Co and Mn), have become one of the mainstream cathode materials for next-generation lithium-ion batteries due to their high capacity and cost efficiency compared with LiCoO 2 . However, the high-voltage operation of the Ni-rich oxides (>4.3 V) required for high capacity is inevitably accompanied with a rapid capacity decay over numerous cycles. In this work, we reported a surface coating of LiNi 0.6 Co 0.2 Mn 0.2 O 2 with Li 2 Si 2 O 5 via a facile and efficient synthetic approach, which involves the employment of silicic acid (H 2 SiO 3 ) as remover to react with the surface residual lithium compounds ( e.g. Li 2 CO 3 and LiOH) of LiNi 0.6 Co 0.2 Mn 0.2 O 2 and consequent formation of a robust and complete Li + -conductive Li 2 Si 2 O 5 protective coating layer . The structure and morphology of the coated cathode materials are fully characterized by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Compared with the pristine LiNi 0.6 Co 0.2 Mn 0.2 O 2 , coating with the Li + -conductive Li 2 Si 2 O 5 is found to be very effective for improving the rate capability of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 when evaluated at a high cut-off voltage up to 4.5 V. Specifically, 1 wt. % H 2 SiO 3 -treated LiNi 0.6 Co 0.2 Mn 0.2 O 2 electrode exhibits high discharge specific capacities of 213.9 and 121.6 mAh g −1 at 0.1 and 10 C, respectively, whereas the pristine electrode only shows 196.8 and 92.1 mAh g −1 . Besides, the surface-modified LiNi 0.6 Co 0.2 Mn 0.2 O 2 electrode also manifests an enhanced long-term cycling stability (67% capacity retention after 200 cycles at 5 C), much better than the pristine electrode (52% retention) due to the robust protective effect of the Li 2 Si 2 O 5 coating layer. All these results indicate that the Li 2 Si 2 O 5 -coated LiNi 0.6 Co 0.2 Mn 0.2 O 2 will be a promising cathode material for lithium-ion batteries with fascinating electrochemical energy storage capabilities.
研究领域:
电化学
·
材料科学
·
能源存储
·
锂离子电池技术
·
固态化学
·
表面改性
✓ 已验证
DOI
高影响因子
Journal of Energy Chemistry
·
2021
·
IF 9.676
Pengfei Zhou,Jing Zhang,Zhennan Che,Zuhao Quan,Ju Duan,Xiaozhong Wu,Junying Weng,Jinping Zhao,Jin Zhou
P2-Na 0.67 Ni 0.33 Mn 0.67 O 2 is considered as a promising cathode material for sodium-ion battery (SIBs) because of its high capacity and discharge potential. However, its practical use is limited by Na + /vacancy ordering and P2-O2 phase transition. Herein, a Ti 4+ /F − co-doping strategy is developed to address these issues. The optimal P2-Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O 1.9 F 0.1 exhibits much enhanced sodium storage performance in the high voltage range of 2.0–4.4 V, including a cycling stability of 77.2% over 300 cycles at a rate of 2 C and a high-rate capability of 87.7 mAh g −1 at 6 C. Moreover, the P2-Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O 1.9 F 0.1 delivers reversible capacities of 82.7 and 128.1 mAh g −1 at −10 and 50 °C at a rate of 2 C, respectively. The capacity retentions over 200 cycles at −10 °C is 94.2%, implying more opportunity for practical application. In-situ X-ray diffraction analysis reveals that both P2-O2 phase transitions and Na + /vacancy ordering is suppressed by Ti 4+ /F − co-doping, which resulting in fast Na + diffusion and stable phase structure. The hard carbon//P2-Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O 1.9 F 0.1 full cell exhibits a high energy density of 310.2 Wh kg −1 and remarkable cyclability with 82.1% retention after 300 cycles at 1 C in the voltage range of 1.5–4.2 V. These results demonstrate that the co-doping Ti 4+ /F − is a promising strategy to improve the electrochemical properties of P2-Na 0.67 Ni 0.33 Mn 0.67 O 2 , providing a facile tactic to develop high performance cathode materials for SIBs.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固态化学
·
电池技术
✓ 已验证
DOI
高影响因子
Advanced Energy Materials
·
2022
·Vol. 12
·期 20
·2200813
·
IF 29.698
Weiyuan Huang,Qi Zhao,Mingjian Zhang,Shenyang Xu,Haoyu Xue,Chen Zhu,Jianjun Fang,Wenguang Zhao,Guoxi Ren,Runzhi Qin,Qinghe Zhao,Haibiao Chen,Feng Pan
LiCoO 2 (LCO) is the most successful cathode material for commercial lithium-ion batteries. Cycling LCO to high potentials up to 4.5 V or even 4.6 V can significantly elevate the capacity but cause structural degradation due to the serious surface side reaction between the highly oxidized Co 4+ and O − species with organic electrolytes. To tackle this concern, a new strategy, constructing cation and anion dual gradients at the surface of LCO (DG-LCO), is proposed. Specifically, the electrochemically inactive cation and anion are selected to substitute Co 3+ and O 2− at the surface in a gradated manner, thus minimizing the highly oxidized Co 4+ and O − species at high potentials and suppressing the induced surface side reactions. Unexpectedly, this dual gradient design leads to a spinel-like surface structure coherently with bulk layered structure, which facilitates Li + diffusion kinetics. Thus, DG-LCO achieves high capacity and excellent cycling stability at 4.6 V (≈216 mA h g −1 at 0.1 C, a capacity retention of 88.6% after 100 cycles in 1.8 A h pouch full cell at 1 C), as well as improved rate capability (≈140 mA h g −1 at 5 C). These studies provide useful guidelines for future design of cathode materials with long lifespan and high rate capability.
研究领域:
材料科学
·
电化学
·
储能
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）