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Candle Soot As High Capacity Anode Materials For Lithium Ion Battery
Project Description :

Since its inception by sony in 1991, lithium (li) ion battery remains most widely used rechargeable batteries for portable energy storage devices in consumer electronics due to their high energy density. recent advances in li ion battery find their potential use beyond consumer electronics, in hybrid and electric vehicles. carbon materials have predominantly used as anodes for li ion battery. although graphite shows low reversible capacity (theoretical li ion intercalation capacity 372 mah/g), it is still most commonly used anode in commercial li ion batteries due to its excellent cyclic performance, lower discharge potential, chemical stability and flat discharge profile. on the other hand, hard, disordered carbons show much higher capacity but suffers from high irreversible capacity losses. however for high performance advance li ion battery for electric vehicle applications, poor rate capability limits the use of both graphite and hard carbons. in addition to carbon materials, several other alternate anode materials such as lithium titanate (lto), sn, si and other metal based alloys and oxides have also been tested in recent years for high rate performance. lto suffers due to limited reversible capacity (theoretical value 175 mah/g) and poor conductivity while si and sn show large volume change while charging/discharging and thereby lack in structural integrity. to overcome these challenges, extensive research efforts are underway suggesting nano-structuring of carbon materials and/or improving their conductivity for enabling their use for high rate capabilities. nano-structuring facilitates in minimizing the diffusion length for li ions for their fast charging/discharging whereas enhanced electronic conductivity allows effective transport of electrons and ionic mobility. in some of these efforts, carbon nanotubes (cnt) and graphene in various forms including nano-composites have been synthesized and tested for their enhanced electrochemical performance. however there are many issues such as increased contact resistance between active material and cnt/graphene, loss of structural integrity at high charge/discharge rates apart from mass scalability for which carbon based nano-composites remained far off from their commercial use. in a recent report, cnt based integrated nano-composites have been suggested as an alternative to high performance anode materials. integrated nanostructures showed robust structural integrity and also long range conductivity owing to intimate interfacial contacts. further only graphene in the form of ribbons, sheets, ink and paper has been tested as anode but shows poor coulombic efficiency even at charge/discharge rate below 1 c. however in another report, photothermally reduced graphene with open-pore structure has been demonstrated as high power anodes with reported capacity nearly 100 mah/g at very high c-rate (100 c). in the present work, we report a facile and inexpensive way to obtain integrated fractal-like network of carbon nanoparticles directly from uncontrolled combustion of candle in the form of soot and successfully demonstrate their use as high performance anode materials with high rate capability. carbon soot has recently created a huge research interest for promising applications in superhydrophobic coatings. in another report, carbon nanoparticls derived from castor oil soot were modified and activated for their use in electroctalytic applications. there are few recent reports on using carbon soot as electrode materials for supercapacitors and dye sensitized solar cells. however to the best of our knowledge, for the first time, we have tested candle soot based fractal-like carbon nanoparticles network as anode materials for li ion battery. in a tight summary, our innovation is based on facile and inexpensive approach to synthesize fractal-like interconnected network of carbon nanoparticles from candle soot and its direct application as anode material for high-rate lithium ion batteries used for electric vehicles. at low charge/discharge rate (0.5 c), an initial discharge capacity was found to be 1997 mah/g with moderate 30% coulombic efficiency that increased to 91% after 10 cycles. more importantly, at very high charge/discharge rate (10 c), reversible capacity was stabilized at 170 mah/g even after 1000 cycles. this remarkable electrochemical performance may be ascribed to unique morphology of these hard carbon nanoparticles that reduces the diffusion length and also allows fast adsorption/desorption of li ions on their surface.

 
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Project Details :
  • Date : Jan 31,2015
  • Innovator : Manohar Kakunuri
  • Guide Name : Dr. Chandra Shekhar Sharma
  • College : Indian Institute of Technology Hyderabad
  • University : Indian Institute of Technology Hyderabad
  • Submission Year : 2015
  • Category : Energy Engineering
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