Nanohybridization of CoS2/MoS2 Heterostructure with Polyoxometalate on Functionalized Reduced Graphene Oxide for High‐Performance LIBs

To address the poor cycling stability and low rate capability of MoS2 as electrode materials for lithium-ion batteries (LIBs), herein, the CoS2 /MoS2 /PDDA-rGO/PMo12 nanocomposites are constructed via a simple hydrothermal process, combining the advantages of all three, namely, CoS2 /MoS2 heterojunction and polyoxometalates (POMs) provide abundant catalytically active sites and increase the multi-electron transfer ability, and the positively charged poly(diallyldimethylammonium chloride) modified reduced graphene oxide (PDDA-rGO) improve electronic conductivity and effectively prevent the aggregation of MoS2 , meanwhile stabilize the negatively charged [PMo12 O40 ]3- . After the electrochemical testing, the resulting CoS2 /MoS2 /PDDA-rGO/PMo12 nanocomposite achieved 1055 mA h g-1 initial specific capacities and stabilized at 740 mA h g-1 after 150 cycles at 100 mA g-1 current density. And the specific capacities of MoS2 , MoS2 /PDDA-rGO, CoS2 /MoS2 , and CoS2 /MoS2 /PDDA-rGO were 201, 421, 518, and 589 at 100 mA g-1 after 150 cycles, respectively. The fact of the greatly improving capacity of MoS2 -based nanocomposites suggests its potential for high performance electrode materials of LIBs. Moreover, the lithium storage mechanism of CoS2 /MoS2 /PDDA-rGO/PMo12 has been discussed on the basis of cyclic voltammetry with different scan rates.