Hong, Seung-Ah Kim, Su Jin Kim, Jaehoon Lee, Byung Gwon Chung, Kyung Yoon Lee, Youn-Woo 2024-01-20T14:04:25Z 2024-01-20T14:04:25Z 2021-09-05 2012-08-01 1385-8947 https://pubs.kist.re.kr/handle/201004/128984 Carbon coating on lithium iron phosphate (LiFePO4) plays a crucial role in determining its electrochemical performance. This study investigates the effect of carbon coating on lithium iron phosphate particles synthesized using a continuous supercritical hydrothermal synthesis (SHS) method and a conventional solid-state (SS) method, with sucrose as a carbon precursor. The carbon content, carbon structure, morphology, electronic conductivity, and electrochemical performance of the carbon-coated LiFePO4 (C-LiFePO4) are characterized as a function of the following coating conditions: sucrose concentration, calcination temperature, and calcination time. The particles produced using supercritical water have a smaller size (400-1000 nm), larger BET surface area of 7.3 m(2)/g, and lower degree of particle aggregation compared with those produced via solid-state synthesis (particle size: 3-15 mu m: BET surface area: 2.4 m(2)/g). The differences in the particle size and particle morphology of the LiFePO4 prepared using the two synthetic methods cause a significant difference in the uniformity of the carbon coating, carbon structure, and electronic conductivity. A more uniform carbon layer coating and greater amount of graphitic carbon are found in the LiFePO4 particles produced via the SS method. This leads to a higher discharge capacity of 147 mA h/g at a current density of 17 mA/g (0.1 C) after 30 cycles when compared with the C-LiFePO4 produced by the SHS method (135 mA h/g). No obvious capacity fading was observed. At a high current of 1700 mA/g (10 C), the delivered capacities of the C-LiFePO4 particles produced via the SS and the SHS methods are 55% and 52% of the theoretical value, respectively, at a carbon content of 6 wt.%. The carbon-coated samples prepared using the SHS and SS methods exhibit similar discharge capacity trends for the carbon content. As the carbon content increased to 6 wt.%, the discharge capacity increased, while a further increase in the carbon content to 10 wt.% resulted in a decrease in the discharge capacity. Thus, the carbon content and particle properties need to be carefully optimized to enhance the electrochemical performance of C-LiFePO4. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved. English ELSEVIER SCIENCE SA ELECTROCHEMICAL PROPERTIES CATHODE MATERIALS CARBOTHERMAL REDUCTION OXIDE NANOPARTICLES WATER COMPOSITE OLIVINES PERFORMANCE PARTICLES CAPACITY Carbon coating on lithium iron phosphate (LiFePO4): Comparison between continuous supercritical hydrothermal method and solid-state method Article 10.1016/j.cej.2012.05.058 1 CHEMICAL ENGINEERING JOURNAL, v.198, pp.318 - 326 CHEMICAL ENGINEERING JOURNAL 198 318 326 scie scopus 000308513500039 2-s2.0-84864314558 Engineering, Environmental Engineering, Chemical Engineering Article ELECTROCHEMICAL PROPERTIES CATHODE MATERIALS CARBOTHERMAL REDUCTION OXIDE NANOPARTICLES WATER COMPOSITE OLIVINES PERFORMANCE PARTICLES CAPACITY Lithium iron phosphate Carbon coating Supercritical hydrothermal synthesis Solid-state method