(103e) Resorcinol-Formaldehyde Based Electrosprayed Carbon Nanospheres: A Novel Anode Material for Lithium Ion Batteries

Synthesis of spherical carbon particles and other structures of carbon have received a considerable attention in last decade because of their potential use in various fields. Uses of carbon particles are presently being developed in broad ranging applications including anode materials in secondary lithium ion batteries, fuel cells and supercapacitors, adsorbents and drug delivery carriers. There are various approaches reported in the literature to synthesize carbon particles. Some of these include chemical vapor deposition, sol-gel emulsification, and templating techniques. However, despite the fact that there is a significant literature on the synthesis of spherical carbon particles, reports on preparation of carbon nanospheres are very few. This study establishes electrospraying to be a facile technique for the production of monodisperse carbon nanospheres. Resorcinol-formaldehyde based organic sol is successfully electrosprayed for the first time to yield RF nanospheres followed by pyrolysis in an inert atmosphere to obtain carbon nanospheres. Our study shows that the size and morphology of these carbon nanoparticles may be manipulated by varying the process parameters such as needle gauge diameter, applied electric potential and flow rate. The following set of parameters, needle gauge 26g, applied electric potential 1.5kV/cm at RF sol flow rate 0.8ml/h yield highly monodisperse carbon nanospheres with average diameter 30.2 ± 7.1 nm. Raman spectroscopy confirmed the amorphous nature of carbon while EDAX analysis also confirmed the higher yield of carbon from resorcinol-formaldehyde based sol. The surface chemistry of these carbon nanospheres was also studied by FTIR in the attenuated total reflection mode which shows the mild presence of ?OH bonds. This explains the weak hydrophilic behavior of the RF derived carbon surfaces. However, interesting wettability behavior is observed with carbon nanoparticles surfaces which show extreme structural hydrophilicity (water contact angle ~ 5-10 degree) in comparison to flat RF sol derived carbon films (water contact angle ~ 80 degree). The carbon nanospheres synthesized here may have a variety of potential applications in the field of adsorbents, drug delivery, bio-sensors, gas and humidity sensing devices, electrode material for batteries, super-capacitors and fuel cells. Our group is currently working on the integration of these carbon nanospheres with carbon microelectrochemical systems (C-MEMS) to enhance their performance. Conformal deposition of carbon nanospheres on high aspect ratio carbon posts as shown in schematic diagram below should greatly increase the external surface area available for intercalation of lithium ions thus increasing the specific capacity of the battery electrode. References: 1. Arya N, Chakraborty S, Dube N and Katti D S 2009 J. Biomed. Mater. Res. Part B: Appl. Biomater. 88B 17. 2. Pekala R W 1989 J. Mater. Sci. 24 3221. 3. Sharma C S, Kulkarni M M, Sharma A and Madou M 2009 Chem. Eng. Sci. 64 1536. 4. Wang C, Zaouk R and Madou M 2006 Carbon 44 3073. 5. Wang Y, Su F, Wood C D, Lee J Y and Zhao X S 2008 Ind. Eng. Chem. Res. 47 2294.