Synthesis of graphene-siloxene nanosheet based layered composite materials by tuning its interface chemistry: An efficient anode with overwhelming electrochemical performances for lithium-ion batteries

Owing to its high theoretical storage capacity, two dimensional (2D) silicon nanosheets is the one among the most exciting anode material for the next generation lithium ion (Li-ion) batteries. However, deprived electrochemical properties due to the huge volume expansion resulting in rapid capacity decay, thereby hindering its commercial application aspect of silicon nanosheet based materials. The present work proposes a novel concept of synthesizing graphene-siloxene (SiG) based multi-layered structures by tuning the interface chemistries of graphene oxide and siloxene sheets derived from topochemical transformation of calcium silicide (CaSi₂). Morphological characterization using Field emission scanning electron microscopic and transmission electron microscopy reveal the successful formation of few- to multi-layered SiG composite materials with intercalated/surface grafted siloxene nanosheets on the graphene layers. Owing to its hierarchical composite structure, SiG as anode delivers the first discharge and charge capacity values as high as 3880 mAhg⁻¹ and 3016 mAhg⁻¹ respectively measured at the current rate of 205 mAg⁻¹. Even at high current rate (4.1 Ag⁻¹), SiG composite materials delivers first charge capacity of 1480 mAhg⁻¹ with good cycling performance (1040 mAhg⁻¹) after 1000 cycles. Due to its enhanced lithium storage, cycling stability and rate capability, synthesized SiG composites could be a potential anode candidate for Li-ion batteries.