title: Morphology-Tuned Synthesis of NiCo2 O4 -Coated 3D Graphene Architectures Used as Binder-Free Electrodes for Lithium-Ion Batteries.
abstract: Nanostructured NiCo2O4 is directly grown on the surface of three-dimensional graphene-coated nickel foam (3D-GNF) by a facile electrodeposition technique and subsequent annealing. The resulting NiCo2O4 possesses a distinct flower or sheet morphology, tuned by potential or current variation electrodeposition, which are used as binder-free lithium-ion battery anodes for the first time. Both samples exhibit high lithium storage capacity, profiting from the unique binder-free electrode structures. The flower-type NiCo2O4 demonstrates high reversible discharge capacity (1459 mAh g(-1) at 200 mA g(-1)) and excellent cyclability with around 71% retention of the reversible capacity after 60 cycles, which are superior to the sheet-type NiCo2O4. Such superb performance can be attributed to high volume utilization efficiency with unique morphological character, a well-preserved connection between the active materials and the current collector, a short lithium-ion diffusion path, and fast electrolyte transfer in the binder-free NiCo2O4 coated 3D graphene structure. The simple preparation process and easily controllable morphology make the binder-free NiCo2O4/3D-GNF hybrid a potential material for commercial applications.
authors.affiliation: Department of Energy Systems Engineering, DGIST, Daegu, 42988, Republic of Korea.
authors.forename: Chunfei
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Energy Systems Engineering, DGIST, Daegu, 42988, Republic of Korea. jsyu@dgist.ac.kr.
authors.forename: Jong-Sung
authors.identifier: http://orcid.org/0000-0002-8805-012X
authors.initials: JS
authors.lastname: Yu
keywords: anodes; graphene; lithium-ion batteries; morphology control; nickel