title: Yolk-shell, hollow, and single-crystalline ZnCo(2)O(4) powders: preparation using a simple one-pot process and application in lithium-ion batteries.
abstract: The electrochemical properties of yolk-shell-structured, multi-component, transition-metal oxides have not yet been properly compared to those of hollow-structured or nanoscale powders. In this study, yolk-shell, hollow, and single-crystalline ZnCo2 O4 powders with uniform compositions are prepared by using simple gas-phase reaction methods. Double-shelled ZnCo2 O4 yolk-shell powder is prepared directly from the spray solution by using spray pyrolysis. Single-crystalline ZnCo2 O4 nanopowder is prepared by means of flame spray pyrolysis. The yolk-shell ZnCo2 O4 powder shows higher charge and discharge capacities than the hollow and single-crystalline powders. The yolk-shell, hollow, and single-crystalline ZnCo2 O4 powders deliver discharge capacities of 753, 586, and 206 mAh g(-1) , respectively, after 200 cycles at a charge/discharge rate of 3 A g(-1) , and the corresponding capacity retentions measured after the first cycle are 99, 74, and 27 %, respectively. The yolk-shell ZnCo2 O4 powders are structurally stable during cycling and have good electrochemical properties even at high current densities.
authors.affiliation: Department of Chemical Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea), Fax: (+82) 2 4583504.
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Yun Chan
authors.initials: YC
authors.lastname: Kang
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D011211:Electric Power Supplies; D004563:Electrochemistry; D008094:Lithium / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D011208:Powders; D013696:Temperature; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D010087:Oxides; D011208:Powders; D017967:Zinc Compounds; D003035:Cobalt; D008094:Lithium
keywords: anode materials; energy conversion; lithium ion batteries; nanoparticles; spray pyrolysis