title: Biomimetic synthesis of metal ion-doped hierarchical crystals using a gel matrix: formation of cobalt-doped LiMn(2)O(4) with improved electrochemical properties through a cobalt-doped MnCO(3) precursor.
abstract: We have synthesized spinel type cobalt-doped LiMn(2)O(4) (LiMn(2-y)Co(y)O(4), 0</=y</=0.367), a cathode material for a lithium-ion battery, with hierarchical sponge structures via the cobalt-doped MnCO(3) (Mn(1-x)Co(x)CO(3), 0</=x</=0.204) formed in an agar gel matrix. Biomimetic crystal growth in the gel matrix facilitates the generation of both an homogeneous solid solution and the hierarchical structures under ambient condition. The controlled composition and the hierarchical structure of the cobalt-doped MnCO(3) precursor played an important role in the formation of the cobalt-doped LiMn(2)O(4). The charge-discharge reversible stability of the resultant LiMn(1.947)Co(0.053)O(4) was improved to ca. 12 % loss of the discharge capacity after 100 cycles, while pure LiMn(2)O(4) showed 24 % loss of the discharge capacity after 100 cycles. The parallel control of the hierarchical structure and the composition in the precursor material through a biomimetic approach, promises the development of functional materials under mild conditions.
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Kokubu
authors.forename: Yuya
authors.initials: Y
authors.lastname: Oaki
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Uchiyama
authors.forename: Eiji
authors.initials: E
authors.lastname: Hosono
authors.forename: Haoshen
authors.initials: H
authors.lastname: Zhou
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Imai
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D002254:Carbonates / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D003460:Crystallization; D055664:Electrochemical Techniques; D005782:Gels / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002254:Carbonates; D005782:Gels; D010087:Oxides; C488552:lithium manganese oxide; D003035:Cobalt; D008345:Manganese; D008094:Lithium; C045327:manganese carbonate