title: Drastically Enhanced High-Rate Performance of Carbon-Coated LiFePO4 Nanorods Using a Green Chemical Vapor Deposition (CVD) Method for Lithium Ion Battery: A Selective Carbon Coating Process.
abstract: Application of LiFePO4 (LFP) to large current power supplies is greatly hindered by its poor electrical conductivity (10(-9) S cm(-1)) and sluggish Li+ transport. Carbon coating is considered to be necessary for improving its interparticle electronic conductivity and thus electrochemical performance. Here, we proposed a novel, green, low cost and controllable CVD approach using solid glucose as carbon source which can be extended to most cathode and anode materials in need of carbon coating. Hydrothermally synthesized LFP nanorods with optimized thickness of carbon coated by this recipe are shown to have superb high-rate performance, high energy, and power densities, as well as long high-rate cycle lifetime. For 200 C (18s) charge and discharge, the discharge capacity and voltage are 89.69 mAh g(-1) and 3.030 V, respectively, and the energy and power densities are 271.80 Wh kg(-1) and 54.36 kW kg(-1), respectively. The capacity retention of 93.0%, and the energy and power density retention of 93.6% after 500 cycles at 100 C were achieved. Compared to the conventional carbon coating through direct mixing with glucose (or other organic substances) followed by annealing (DMGA), the carbon phase coated using this CVD recipe is of higher quality and better uniformity. Undoubtedly, this approach enhances significantly the electrochemical performance of high power LFP and thus broadens greatly the prospect of its applications to large current power supplies such as electric and hybrid electric vehicles.
authors.affiliation: †National Center for Nanoscience and Technology of China, Beijing 100190, P. R. China.
authors.forename: Ruiyuan
authors.initials: R
authors.lastname: Tian
authors.affiliation: †National Center for Nanoscience and Technology of China, Beijing 100190, P. R. China.
authors.forename: Haiqiang
authors.initials: H
authors.lastname: Liu
authors.affiliation: †National Center for Nanoscience and Technology of China, Beijing 100190, P. R. China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: †National Center for Nanoscience and Technology of China, Beijing 100190, P. R. China.
authors.forename: Jiankun
authors.initials: J
authors.lastname: Chen
authors.affiliation: †National Center for Nanoscience and Technology of China, Beijing 100190, P. R. China.
authors.forename: Xinghua
authors.initials: X
authors.lastname: Tan
authors.affiliation: §China University of Geosciences, Beijing 100083, P. R. China.
authors.forename: Guangyao
authors.initials: G
authors.lastname: Liu
authors.affiliation: ‡Department of Physics, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Lina
authors.initials: L
authors.lastname: Zhang
authors.affiliation: ‡Department of Physics, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Gu
authors.affiliation: †National Center for Nanoscience and Technology of China, Beijing 100190, P. R. China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Guo
authors.affiliation: †National Center for Nanoscience and Technology of China, Beijing 100190, P. R. China.
authors.forename: Hanfu
authors.initials: H
authors.lastname: Wang
authors.affiliation: †National Center for Nanoscience and Technology of China, Beijing 100190, P. R. China.
authors.forename: Lianfeng
authors.initials: L
authors.lastname: Sun
authors.affiliation: †National Center for Nanoscience and Technology of China, Beijing 100190, P. R. China.
authors.forename: Weiguo
authors.initials: W
authors.lastname: Chu
keywords: CVD method; carbon coating; high power density; high-rate performance; hydrothermal method; lithium iron phosphate