Welcome to Dr. Singh's lab

RESEARCH PROJECTS

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• New type of polymer-derived ultrahigh temperature materials: Novel polymeric precursors for synthesis of multifunctional ceramics such as Si-B-C-N, Si-Al-O-C etc. These materials possess unique high temperature mechanical, optical, and electrical properties and currently being explored for use in jet engine and related applications. 

• Advanced thermal and optical coatings: Advanced optical coatings of carbon nanotube and graphene modified ceramic nano-materials for laser thermal detectors and other applications that require protection under harsh conditions. Goal here is to develop materials that can absorb from UV to far infrared and yet tolerate the intense heat-flux from high-energy laser irradiation.

• Manufacture of 2-D nano-materials and hybrid composites for use in energy storage devices:

  • High capacity, lightweight flexible battery electrodes from exfoliated layered transition metal dichalcogenides (TMDs). TMDs are 2-D materials similar to graphene with unique chemical and physical properties.

  • Fundamental understanding of charge storage mechanisms in 2-D materials: Goal here is to understand the origins of irreversibility and voltage hysteresis in electrodes comprising of various graphene derivatives and develop tools to mitigate first cycle loss and energy inefficiency in order to design efficient batteries and super-capacitors.

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Impact Publications

1.    L. David, R. Bhandavat, and G. Singh*. Large Area MoS2/graphene Composite Paper Based Electrode for 

Room Temperature Na-ion Batteries: Electrochemical and Mechanical Characterization. ACS Nano, 8 (2), pp 1759–1770 (2014). Citations: 1057

Prof. Singh and students were the first to report on mechanical and electrochemical testing of a new kind of composite consisting of layered graphene and molybdenum disulfide for sodium ion batteries. Flexible paper-like material made from graphene and molybdenum disulfide fixed swelling of electrodes in sodium-ion batteries. This work was later patented by Prof. Singh and student [U.S. Patent No. 10,950,850. The work was highlighted in IEEE Spectrum Magazine:

http://spectrum.ieee.org/nanoclast/semiconductors/nanotechnology/graphene-composite-offers-critical-fix-for-sodiumion-batteries 

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2.    R. Bhandavat, L. David and G. Singh*. Synthesis of Surface Functionalized WS2 Nanosheets and Performance as Li-Ion Battery Anode. Journal of Physical Chemistry Letters 3 (11), 1523–1530 (2012). Citations: 355

Highlighted in Science Daily, PhysOrg, Azo-Nano, ChemViews, and IEEE Spectrum magazine.

 

3.    L. David, R. Bhandavat, U. Barrera, and G. Singh*. Silicon Oxycarbide Glass-Graphene Composite Paper 

Electrode for Long-Cycle Lithium-ion Batteries. Nature Communications, 7, Article number: 10998 doi:10.1038/ncomms10998 (2016). Citations: 289

Silicon electrodes when used in Li-ion batteries tend to crack and break after just a short number of charge/discharge cycles. Meanwhile, the use of graphene on electrodes is limited because graphene’s attractive surface area is only possible in single stand-alone sheets, which don’t provide enough volumetric capacitance. Layer the graphene sheets on top of each other to gain that volumetric capacity, and you begin to lose that attractive surface area. Prof. Singh and student developed a technique that uses a new type of silicon-based ceramic material--silicon oxycarbide that makes the combination of silicon and graphene achieve its expected greatness as an electrode material. Stable cycling in Li-ion batteries up to 1000 cycles was demonstrated without capacity degradation. This work is considered among this most significant works on bendable electrodes for Li-ion batteries. Prof. Singh also have patent on this material [U.S. Patent No. 10,950,850]. News media: http://spectrum.ieee.org/nanoclast/semiconductors/materials/potential-of-silicon-and-graphene-together-for-liion-electrodes-realized  

 

4.    L. David, and G. Singh*. Reduced Graphene Oxide Paper Electrode: Opposing Effect of Thermal Annealing on Li and Na Cyclability. Journal of Physical Chemistry-C, 118 (49), pp 28401–28408 (2014). Citations: 164

 

5.    R. Bhandavat and G. Singh*. Stable and Efficient Li-Ion Battery Anodes Prepared from Polymer-Derived 

Silicon Oxycarbide–Carbon Nanotube Shell/Core Composites. The Journal of Physical Chemistry C, 117 (23), 11899–11905 (2013). Citations: 92

 

6.    R. Bhandavat, A. Feldman, C. Cromer, J. Lehman, and G. Singh. Very High Laser-damage Threshold of Polymer-Derived Si (B) CN-Carbon Nanotube Composite Coatings. ACS-Applied Materials & Interfaces, 5 (7), 

2354–2359 (2013). Citations: 58 

During the last 100 years, thermal detector coatings based on carbon-based paints, diffuse metals (gold black, silver black), oxidized metals and other materials have been investigated about spectral uniformity and resistance to damage and aging. Such coatings, however, are vulnerable to damage at high optical powers from forced air, as well as aging and hardening at UV wavelengths. To address this challenge, Prof. Singh and colleagues demonstrated synthesis of a silicon-based ceramic/carbon nanotube shell/core composite. Such coatings show high optical absorbance (98 % from UV for IR) and an unprecedented thermal damage resistance of more than 15 kW.cm-2 at 10.6 μm, highest reported value for any material to date. This material has been patented by Singh and student [U. S. Patent No. 9,453,111]. It was also highlighted in NIST Technical Beat, http://www.nist.gov/pml/div686/nanotubes-041713.cfm 

 

7.    L. David, A. Feldman, E. Mansfield, J. Lehman, and G. Singh*. Evaluating Thermal Damage Resistance of 

Graphene/Carbon Nanotube Hybrid Composite Coatings. Scientific Reports (Nature Publishing Group) 4, Article number: 4311 (2014). Citations: 39 

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8.    L. David, D. Asok, and G. Singh*. Synthesis and Extreme Rate Capability of Si–Al–C–N Functionalized 

Carbon Nanotube Spray-on Coatings as Li-Ion Battery Electrode. ACS-Applied Materials & Interfaces, DOI: 10.1021/am5052729 (2014). Citations:  28

A new kind of liquid polymer was developed that can be transformed into ultrahigh temperature ceramic upon heating. The liquid polymer may also be used in 3-D printing of ceramics. The waterlike polymer, which becomes a ceramic when heated, also can be mass-produced. This work was later patented by Prof. Singh and student [U.S. Patent No. 9,908,905].

 

9.    G. Singh*, P. Rice, R.L. Mahajan, and J.R. McIntosh. Fabrication and Characterization of a CNT Based Nano-Knife. Nanotechnology, 20, 095701 (2009). Citations: 22

This work, performed by Professor Singh as PhD student was the first demonstration of fabrication and mechanical testing of a carbon nanotube-based compression cutting tool for biological applications. 

This work was highlighted in Nanowerks and Singh interviewed for History Channel Modern Marvels—World’s Sharpest: https://www.nanowerk.com/spotlight/spotid=9315.php

 

10.    G. Singh*, P. Rice, R.L. Mahajan, and J.R. McIntosh. Fabrication and Mechanical Characterization of a Force Sensor Based on an Individual Carbon Nanotube. Nanotechnology, 18, 475501 (2007). Citations:  31