title: LiNi₁/₃Co₁/₃Mn₁/₃O₂-graphene composite as a promising cathode for lithium-ion batteries.
abstract: The use of graphene as a conductive additive to enhance the discharge capacity and rate capability of LiNi(1/3)Co(1/3)Mn(1/3)O(2) electrode material has been demonstrated. LiNi(1/3)Co(1/3)Mn(1/3)O(2) and its composite with graphene (90:10 wt %) were prepared by microemulsion and ball-milling techniques, respectively. The structural and morphological features of the prepared materials were investigated with powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Characterization techniques depict single-phase LiNi(1/3)Co(1/3)Mn(1/3)O(2) with particle sizes in the range of 220-280 nm. Electrochemical studies on LiNi(1/3)Co(1/3)Mn(1/3)O(2) and LiNi(1/3)Co(1/3)Mn(1/3)O(2)-graphene were conducted using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy methods by constructing a lithium half-cell. Cyclic voltammograms show the well-defined redox peaks corresponding to Ni(2+)/Ni(4+). Charge-discharge tests were performed at different C rates: 0.05, 1, and 5 between 2.5 and 4.4 V. The results indicate the better electrochemical performance of the LiNi(1/3)Co(1/3)Mn(1/3)O(2)-graphene composite in terms of high discharge capacity (188 mAh/g), good rate capability, and good cycling performance compared to LiNi(1/3)Mn(1/3)Co(1/3)O(2). The improved electrochemical performance of the LiNi(1/3)Co(1/3)Mn(1/3)O(2)-graphene composite is attributed to a decrease in the charge-transfer resistance.
authors.affiliation: Department of Chemistry, University of Puerto Rico, San Juan, Puerto Rico 00931, United States. vrao.chitturi@ymail.com
authors.forename: Chitturi
authors.initials: C
authors.lastname: Venkateswara Rao
authors.forename: Arava
authors.initials: A
authors.lastname: Leela Mohana Reddy
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Pulickel M
authors.initials: PM
authors.lastname: Ajayan
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D011211:Electric Power Supplies; D055664:Electrochemical Techniques; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008094:Lithium / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*
chemical_list: D007477:Ions; D010087:Oxides; D003035:Cobalt; D008345:Manganese; D006108:Graphite; D008094:Lithium