NiCo[sub 2]O[sub 4]/C Nanocomposite as a Highly Reversible Anode Material for Lithium-Ion Batteries

Abstract

A NiCo 2 O 4 /C nanocomposite has been synthesized by a hydrothermal method followed by a calcination. X-ray powder diffraction and transmission electron microscopy measurements demonstrated the composite was composed of crystalline NiCo 2 O 4 and amorphous carbon, and NiCo 2 O 4 and carbon particles amalgamated together with good affinity. The electrochemical results showed as high as 914.5 mAh/g reversible capacity could be achieved at 40 mA/g current density in the potential range of 0.01Ϫ3.0 V. The initial coulombic efficiency of the composite was 79.2%, and the capacity retention was 78.3% up to 50 cycles. The superior electrochemical performance indicated that the NiCo 2 O 4 /C nanocomposite might be a promising alternative to conventional graphite-based anode materials for lithium-ion batteries.During the past decade, research on anode materials for lithiumion batteries mainly focused on searching for carbon alternatives with larger capacities and better cycling performances. 1,2 Conversion reactions have opened a new line of research in the field of electrode materials for Li-ion batteries. It was found that transitionmetal oxides ͑MO, where M is Co, Ni, Cu, or Fe͒ can be reduced to their metal state and then be reoxidized, providing a large reversible capacity ͑700 mAh/g͒, good cycling performance, and high recharge rates. 3 The reaction mechanism of these metal oxides by lithium involved the reversible reduction and oxidation of metal ͑M͒ nanosized particles dispersed into a lithia matrix ͑Li 2 O͒, followed by the formation/decomposition of a solid electrolyte interface ͑SEI͒. It was found that the electrochemical properties of the electrodes were related to factors such as the large change in volume, the serious aggregation or pulverization of active particles during chargedischarge, and poor conductivity of the transition metal oxides. 4 In previous work, it has further been proposed that mixed transition metal oxides such as NiCo 2 O 4 , 5 NiFe 2 O 4 , 6 and CoFe 2 O 4 , 7-9 can react reversibly with larger amounts of lithium and the preparation methods have a crucial effect on electrochemical performance in long-term cycling. 7 Due to its relatively high electrical conductivity and infrared transparency, NiCo 2 O 4 has been developed as an alternative electrode material for supercapacitors 10-12 and used as a heterogeneous optical recording media. 13 Moreover, the electrochemical properties have been studied widely in alkaline medium for the oxygen evolution reaction. The preparation methods include thermal decomposition, 5,14 solution deposition, 15 combinatorial sputtering deposition, 16 single-target sputter deposition, 16 and hydroxide coprecipitation, 17 etc.It is well known that hydrothermal synthesis has been shown to be advantageous over other methods in homogeneous nucleation and grain growth. 18 In the work reported here, we describe an easy route to isochronously synthesize NiCo 2 O 4 /C nanocomposite via a lowtemperature hydrothermal method followed by calcination, using poly͑ethylene gl...

A Simple Synthesis of Two-Dimensional Ultrathin Nickel Cobaltite Nanosheets for Electrochemical Lithium Storage

“…While two broad oxidation peaks are observed at around 1.50 and 2.20 V in the anodic process, which correspond to the decomposition of electrolyte and Li 2 O accompanying with the multi-step oxidation of metallic cobalt and nickel to Co 3+ and Ni 2+ , respectively, (Eqs. (2)-(4)) [18,21,49]. In comparison with the first cycle, the major cathodic peak shows a decrease in intensity present in the first electrochemical procedure, which could be attributed to the irreversible capacity loss partly caused by the SEI formation.…”

Mesoporous NiCo2O4 nanoneedles grown on three dimensional graphene networks as binder-free electrode for high-performance lithium-ion batteries and supercapacitors

“…In the first cathodic scan, an obvious reduction peak located at ~0.87 V is observed, which can be due to the reduction of Ni 2+ and Co 3+ to metallic Ni and Co, alongLi 2 O decomposes[64]. In the subsequent scans, the main reduction peak at ~0.87 V shifts to ~1 V and the peak intensity dramatically decrease, indicates that some irreversible processes have occurred.…”

Pineapple-shaped ZnCo2O4 microspheres as anode materials for lithium ion batteries with prominent rate performance

“…Therefore, many methods have been developed to fabricate various morphologies of Co 3 O 4 and improve their electrochemical properties. [24][25][26][27][28][29] Because zinc and cobalt are both electrochemically active to lithium, they contribute to lithium storage in a complementary manner. 22 Also, porous Co 3 O 4 nanocapsules were successfully produced via a solvothermal route and a subsequent calcination process.…”