RESUMEN
Nanoporous MnO frameworks with highly dispersed Co nanoparticles were produced from MnCO3 precursors prepared in a gel matrix. The MnO frameworks that contain 20 mol% Co exhibited excellent cycle performance as an anode material for Li-ion batteries. The solid-electrolyte interphase (SEI) formed in the frameworks through the electrochemical reaction mediates the active materials, such as MnO, Mn, and Li2O, during the conversion reaction in the charge-discharge cycle. The Co nanoparticles and SEI provide the electron and Li-ion conductive networks, respectively. The ternary nanocomposites of the MnO framework, metallic Co nanoparticles, and embedded SEI are categorized as durable anode materials for Li-ion batteries.
RESUMEN
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.