Do we need covalent bonding of Si nanoparticles on graphene oxide for Li-ion batteries?

Abstract

In this manuscript, we report our investigation of anode materials for Li-ion batteries based on silicon-graphene oxide composites. Previous reports in the literature on silicon-graphene oxide (GO) composites as anodes have shown a large discrepancy between the electrochemical properties, mainly capacity and coulombic efficiency. In our research, the surface chemistry of Si nanoparticles has been functionalized to yield a chemical bond between the Si and GO, a further annealing step yields a Si-reduced GO (Si-rGO) composite while controlled experiments have been carried on mechanical mixing of GO and Si. For all samples, including a simple mixing of Si nanoparticles and GO, a high specific capacity of 2000 mA h g(Si)(-1) can be achieved for 50 cycles. The main difference between the samples can be observed in terms of coulombic efficiency, which will determine the future of these composites in full Li-ion cells. The Si-rGO composite shows a very low capacity fading and a coulombic efficiency above 99%. Furthermore, the Si-rGO composite can be cycled at very high rate to 20 C (charge in 3 minutes).

Design Considerations for Unconventional Electrochemical Energy Storage Architectures

“…In the fi rst method, the graphene sheets are fi rst homogeneously dispersed into the active material precursor solution followed by subsequent chemical, solvothermal or thermal processing to synthesize the active material. [ 410,458,[565][566][567][568][569][570][571][572][573][574][575][576][577][578][579] In the vapor-phase route, the active material is usually deposited at high temperature on pre-assembled graphene sheets. [ 580,581 ] The amount and the morphology of the synthesized materials can be precisely controlled by the applied chemistry.…”

Critical Insight into the Relentless Progression Toward Graphene and Graphene‐Containing Materials for Lithium‐Ion Battery Anodes

“…Although no description of the material density was reported, this study proved the extremely promising properties of graphene as enhanced carbon matrix in composites. Besides the advances in 3D architectures, investigations on different metal-oxide- [282][283][284][285] and semimetal- [286][287][288][289] containing graphene hybrids proceeded. Generally, an enhancement of the stability upon cycling could be always noticed with respect to the composites developed in the previous years.…”

Novolac phenolic resin and graphene aerogel organic-inorganic nanohybrids: High carbon yields by resin modification and its incorporation into aerogel network

“…This clearly shows that stacking order is reduced and layers are exfoliated [34,53]. GOFASi shows a small peak at 512 cm -1 which corresponds to the presence of silicon [55,56]. Interestingly, GA shows a very different spectrum compared with the others.…”

“…Very high value of I D /I G for GA shows that the size of continuos areas of sp 2 carbon is very small while sp 3 carbon is dominant, which is also resulted from the aerogel network formation. Additionally, the peaks at 545 and 1060 cm -1 are attributed to Si-O network [55,58] and the peaks at 742 and 946 cm -1 are assigned to Si-C group [59,60]. to GO in the diffraction pattern of GOFA and GOFASi, which clearly shows that layers are disordered during the modification processes [62].…”