An insight into the effect of g-C3N4 support on the enhanced performance of ZnS nanoparticles as anode material for lithium-ion and sodium-ion batteries

In this manuscript, the effect of adding graphitic carbon nitride (g-C3N4) on the electrochemical properties of ZnS conversion alloying anode has been investigated in detail. A cooperative phenomenon is observed in case of the ZnS/g-C3N4 composite anodes both in the lithium-ion and sodium-ion half-cell configuration. The ZnS nanoparticles render high capacity and gets lodged in the g-C3N4 nanosheets synthesized using acid assisted sonication method and leads to a synergistic effect which prevents restacking of layers and agglomeration of nanoparticles. The 0.7ZnS:0.3g-C3N4 composite delivers long term reversible capacity of ~596.9 mAh g−1 after 1150 cycles and ~432.6 mAh g−1 after 750 cycles in Li+/Na+ half-cell configuration, respectively, at a high current density of 1 A g−1. The structural and electrochemical investigation of the bare ZnS and ZnS/g-C3N4 composite anodes along-with post-mortem SEM and TEM analysis has been discussed. The enhanced rate capability of the 0.7ZnS:0.3g-C3N4 electrode can be attributed to a fairly prominent role played by capacitive charge storage. The deleterious volume alteration effect during the shuttling of Li+/Na+ ions in ZnS is mitigated by the presence of g-C3N4 and it renders a high reversible capacity and initial coulombic efficiency to the composite anodes which has been studied via ex-situ X-ray photoelectron spectroscopy.