Morphological Effect of Graphene Nanosheets on Ultrathin CoS Nanosheets and Their Applications for High-Performance Li-Ion Batteries and Photocatalysis

Abstract

A unique CoS-graphene sheet-on-sheet nanocomposite has been successfully prepared by anchoring CoS nanosheets on the surface of graphene nanosheets (GNS) with the assistance of the structure-directing agent of ethylenediamine. The shape and size of the introduced CoS nanosheets can be further adjusted by varying the amount of GNS. The unprecedented sheet-like CoS structure is believed to be matched well with GNS basically due to their similar two-dimensional structure with maximum contact areas between two components. The strong interaction between CoS and the underlying highly conductive graphene can facilitate fast electron and ion transport and improve structure stability of the composite. The composite with 26.2% GNS displays excellent electrochemical performance when evaluated as an anode for rechargeable lithium-ion battery. A larger-than-theoretical reversible capacity of 898 mAh/g can be delivered after 80 cycles at 0.1 C along with excellent highrate cycling performance. The CoS-graphene sheet-on-sheet composite is also used for the first time as a photocatalyst with promising properties for the degradation of methylene blue.

Hierarchical NiCo2S4 hollow spheres as a high performance anode for lithium ion batteries

“…Cyclic voltammetry (CV) is initially used to evaluate the lithium storage properties. On the above analysis and previous reports 28,45,46 , the redox reactions can be described as follows: NiCo 2 S 4 +8Li + +8e -→Ni + 2Co +4Li 2 S (1) Ni + Li 2 S ↔ NiS + 2Li 6a, the cathodic peak centered at 1.06 V is attributed to the reduction of Co 3+ and Ni 2+ to metallic Co and Ni, respectively.…”

Two-Dimensional Mesoporous Cobalt Sulfide Nanosheets as a Superior Anode for a Li-Ion Battery and a Bifunctional Electrocatalyst for the Li–O2 System

“…Hence, thereversible capacity of ~642 mAh g -1 (~71%) only retained after 60 cycles compared to ~954 mAh g -1 for CS-4 NS (retention of ~96%). Compared with previous reports on Co 3 S 4 /graphene composite, the pristineCo 3 S 4 -NSdelivered excellent battery performance 17,21,[36][37][38] . Further, it is worth to mention that the shape of the discharge curves of CS-4 NS remains same after 60 cycles, whereas dramatic change in the nature of the curves are noted for CS-3 NS.…”

Microwave Hydrothermal Synthesis of Ni-based Metal–Organic Frameworks and Their Derived Yolk–Shell NiO for Li-Ion Storage and Supported Ammonia Borane for Hydrogen Desorption

“…8−16 LIB, one of the most important rechargeable batteries, have been widely used due to their high energy density and long cycle life. 10,17,18 Metal oxides such as NiO have long been extensively investigated as a potential electrode material for LIBs because of their 2−3 times higher theoretical capacities than commercial graphite electrodes. 19−42 However, their cycling performances and high-rate capabilities are still not satisfactory due to the large volume change associated with lithium insertion and extraction and poor electrical conductivity.…”