The electrochemical performance of aqueous rechargeable lithium battery (ARLB) with LiV3O8 as the anode and LiMn2O4 as the cathode in saturated LiNO3 electrolyte is studied. In an attempt to improve the cycle performance of the as-assembled ARLB, coating with NiO nanofibers on the surface of the anode has been proposed via in situ chemical precipitation method. The influences of the coating on the structure, morphology, and electrochemical properties of LiV3O8 have been characterized by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge experiments. Cycling tests reveal that the stability of the ARLB with NiO coated anode has been greatly improved. Moreover, the rate capability of the ARLB with coated anode is also enhanced compared with the ARLB with bare anode. The improvement of electrochemical properties for ARLB with coated anode can be attributed to NiO coating improves the stability of LiV3O8 in the aqueous electrolyte effectively. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.044208jes] All rights reserved.
Tavorite-like structure LiFePO4F has been recently studied as potential alternative cathode materials for lithium-ion batteries due to its outstanding structural stability, abundant resources and remarkable safety. However, its poor electronic conductivity and lithium-ion diffusion coefficient leads to the unsatisfactory cycling stability and rate capabilities of LiFePO4F. Herein, Ag decorated LiFePO4F nanospheres have been synthesized for the first time via a precipitation method with in-situ reduction of Ag+, simultaneously improving electronic conductivity and lithium-ion diffusion coefficient. The Ag nanoparticles with size of -10 nm are in-situ grown on the surface of LiFePO4F nanospheres with impressive electrochemical performance. It delivers a high discharge capacity of 148.7 mAh g(-1) (very close to the theoretical capacity of 152 mAh g(-1)) at 0.1 C. It is worth mentioning that the Ag-decorated LiFePO4F nanospheres reveal superior cycling stability. The initial discharge capacities of Ag-decorated LiFePO4F reaches up to 120.3 mAh.g(-1) at 0.5 C, and the capacity retention is as high as 96.1% after 300 cycles, which is remarkable higher than that of pure LiFePO4F nanospheres with initial discharge capacity of 110.2 mAh.g(-1) and capacity retention of 83.1% after 300 cycles. Furthermore, the Ag-decorated LiFePO4F displays the average discharge potential loss of only 0.7% which is lower than pure LiFePO4F of 4.7% after 300 cycles, and the corresponding specific energy retention ratio of 95.5% which is higher than that of 80.1%. (C) 2018 Elsevier B.V. All rights reserved.
Tavorite-structured lithium transition metal fluorophosphates have been considered as a good alternative to olivine-type cathode for lithium-ion batteries due to its exceptional ionic conductivity and excellent thermal stability. In this work, nearly monodisperse LiFePO4F nanospheres with high purity are successfully synthesized by a solid-state route associated with chemically induced precipitation method for the first time. The synthesized LiFePO4F presents nearly monodisperse nanospheres particles with average particle size of similar to 500 nm. Cyclic voltammetry data exhibit a clear indication of the Fe3+/Fe2+ redox couple that involves a two-phase transition. Its electrochemical behaviors are examined by galvanostatic charge-discharge. The results show that the initial discharge capacity is 110.2 mAh g(-1) at 0.5 C, after 200 cycles is still retained 104.0 mAh g(-1) with the retention rate of 94.4%. The excellent cycle performance is mainly attributed to the uniform nanospheres-like morphology which is not only beneficial to shorten the transport distance of ions and electrons, but also improve the interface area between electrode and electrolyte, and thus improve the kinetics of Li ions.
Journal of Power Sources,2015年281:85-93 ISSN：0378-7753
[Wang, Xianyou; Wen, Weicheng; Shu, Hongbo; Yang, Xiukang; Chen, Shuhua] Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, School of Chemistry, Xiangtan University, Xiangtan, Hunan, China
Journal of Power Sources,2015年283:204-210 ISSN：0378-7753
[ Shu, Hongbo ; Wang, Xianyou ; Jiang, Miaoling ; Shen, Yongqiang ; Hu, Hai ; Yang, Xiukang ] Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, School of Chemistry, Xiangtan University, Hunan, Xiangtan, China
Anode material - Anode material for lithium ion batteries - Electrochemical analysis - Electrochemical performance - Electrochemical process - Electrochemical reactions - Intercalation mechanisms - Sodium ion batteries