ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Jianfeng Jia,Chuhao Tan,Mengchuang Liu,De Li,Yong Chen
In Li-ion batteries, memory effect has been found in several commercial two-phase materials as a voltage bump and a step in the (dis)charging plateau, which delays the two-phase transition and influences the estimation of the state of charge. Although memory effect has been first discovered in olivine LiFePO4, the origination and dependence are still not clear and are critical for regulating the memory effect of LiFePO4. Herein, LiFePO4 has been synthesized by a home-built spray drying instrument, of which the memory effect has been investigated in Li-ion batteries. For as-synthesized LiFePO4, the memory effect is significantly dependent on the relaxation time after phase transition. Besides, the voltage bump of memory effect is actually a delayed voltage overshooting that is overlaid at the edge of stepped (dis)charging plateau. Furthermore, we studied the kinetics of LiFePO4 electrode with electrochemical impedance spectroscopy (EIS), which shows that the memory effect is related to the electrochemical kinetics. Thereby, the underlying mechanism has been revealed in memory effect, which would guide us to optimize two-phase electrode materials and improve Li-ion battery management systems.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Xiaofei Sun,Xiangguo Hou,Xuesong Mei,Yanbin Han,Bin Liu,Quansheng Li,Zikang Wang,Wei Tang,Yuping Wu,Wenjun Wang,Jianlei Cui
High-capacity rechargeable batteries are crucial for portable electronics, electric vehicles, and smart power grids. High-quality porous Al current collectors with well-designed hole size and hole density are expected to strengthen lithium transportation as well as to accommodate volume variations during fast charging and discharging. Ultrafast femtosecond laser drilling is exploited in this paper to fabricate 3D porous current collectors with precisely controlled hole size and porosity. With optimized laser processing parameters, a series of high-quality porous Al foils with different hole diameters and porosities are designed, simulated, and prepared to investigate their influence on the battery performance of the LiFePO4 electrode. The electrode using laser-drilled Al foil with a hole diameter of 60 μm and a porosity of 15% shows pretty high capacities at various charge/discharge rates. The performance improvement is ascribed to the large roughness and high surface area of the 3D Al foil, the strong connection between electrode materials and the porous current collector, the high loading density and efficient utilization of active materials, the good wettability and facile penetration of the electrolyte and, thus, the high Li+ diffusivity, and the buffering of volume/stress variation during charging/discharging in the 3D porous electrode.
研究领域:
材料科学
·
能源技术
·
电池工程
✓ 已验证
DOI
高影响因子
SOLID STATE IONICS
·
2014
·
IF 2.112
Borong Wu,Yonghuan Ren,Daobin Mu,Xiaojiang Liu,Guchang Yang,Zhe Sun
Sodium chloride (NaCl), as an attractive electrolyte additive , was added in a low temperature electrolyte to investigate its effect on LiFePO 4 electrode. A capacity as high as 115 mAh g − 1 was delivered at 2 C, which was 20 mAh g − 1 more than its NaCl free counterpart. Cyclic voltammetry (CV) tests showed that the polarization of electrode reaction decreased. SEM and XPS measurements were conducted and the result illustrated that the film was modified by NaCl to be uniform containing less resistive LiF, so the transport of Li + through the film was facilitated. Moreover, the conductivity of Li + through electrolyte was also enhanced in the presence of NaCl. NaCl effectively facilitated lithium ion transport rate to the electrode surface and improved the lithiation/delithiation behavior in the LiFePO 4 electrode.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 44
·期 3
·791-796
·
IF 3.069
Yi Di,Suping Jia,Xiaoshuang Yan,Junfei Liang,Shengliang Hu
The development of self-chargeable lithium-ion batteries is of great significance for expanding the usable range of the lithium-ion battery and it has received intensive attention from numerous researchers. Solar cells can generate electricity from the sunlight and ensure sustainable access to electrical power for charging lithium-ion batteries. Herein, a photo-charging integrated device is constructed by combining four conventional dye-sensitized solar cells and a three-electrode hybrid lithium-ion battery, including a dye-sensitized TiO2 photo-anode, LiFePO4 electrode and metal lithium electrode. When the device is operated under solar illumination, DSSCs can match the charging voltage for the hybrid lithium-ion battery. The LiFePO4 electrode in the three-electrode device plays two roles, serving as a reversible redox agent for the regeneration of dye and as the cathode for lithium-ion batteries. The integrated device can effectively harvest solar energy and store it in situ within the hybrid lithium-ion battery through the photo-charging process. The proposed strategy is in favor of exploiting the small-sized, light-weight, self-chargeable battery and may have the potential to be employed as the power supply for miniaturized sensors and mobile devices.
研究领域:
材料科学
·
能源技术
·
电化学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Lei Wang,Jiawei Yan,Ran Zhang,Yanfang Li,Wenzhuo Shen,Jiali Zhang,Min Zhong,Shouwu Guo
Gel electrolytes show certain advantages over conventional liquid and solid electrolytes, but their mechanical strength and surface adhesion to the electrode remain to be improved. To address the challenges, we design and fabricate herein the core–shell nanofiber mats in situ on the LiFePO4 electrode as matrices for gel electrolytes, in which the core is poly(m-phenylene isophthalamide) (PMIA) nanofiber and the shell are composite of Al2O3 nanoparticles and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP). The mechanical property of the core–shell polymeric nanofiber mats and their surface interaction with LiFePO4 electrode are characterized complementarily using dynamic thermomechanical analysis and scanning electron microscopy. The electrochemical properties of the gel electrolytes based on the as-prepared matrices after being loaded with lithium salt solution are studied systematically on half coin cells. It is found that the ultimate strength of the core–shell PMIA@PVdF-HFP/Al2O3 mat can reach 6.70 MPa, 2 times higher than that of the PVdF-HFP/Al2O3 nanofiber mat. Meanwhile, the shell PVdF-HFP/Al2O3 can ensure manifest surface affinity to the LiFePO4 electrode and enhance lithium-ion conductance. Thus, the as-assembled LiFePO4 half coin cells using PMIA@PVdF-HFP/Al2O3 gel electrolyte show good electrochemical performances, especially the long cycle stability with the capacity retention of 96.6% after 600 cycles under 1C.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2020
·Vol. 10
·期 49
·29362-29372
·
IF 3.119
Lingzhu Zhao,Zhipeng Sun,Hongbing Zhang,Yuli Li,Yan Mo,Feng Yu,Yong Chen
Lithium iron phosphate (LiFePO4) is one of the most widely used cathode materials of lithium ion batteries. However, its commercial binder polyvinylidene fluoride (PVDF) is costly, less environmental-friendly and unstable during the long cycling process because of the weak van der Waals forces between the PVDF binder and electrode materials. Herein, an aqueous binder was designed using methacrylate-modified gelatin through UV photo-crosslinking. The crosslinked network and specific functional groups (carboxyl and amino) of the gelatin binder are superior in stabilizing the LiFePO4 electrode structure during long cycles by mitigating the formation of cracks and suppressing the detachment of electrode materials from the Al current collector. The LiFePO4 electrode with gelatin binder displays a high capacity of 140.3 mA h g−1 with 90.1% retention after 300 cycles at 0.5C, which are both superior to that of the PVDF binder (only 114.4 mA h g−1 and 74.8%). This work provides a promising binder to replace the commercial PVDF binder for practical application in energy storage systems.
研究领域:
材料科学
·
电化学
·
能源存储系统
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）