High Capacity Lithium-ion Batteries By MWNTs-in-SnO2
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Common Types of Batteries
*Cylindrical type : used in large portable devices
*Pouch type: smaller lightweight devices
*Prismatic type: electric vehicles and solar battery banks
Figure 1: Types of Li-ion batteries.
Description of Current Lithium
Renewable Energy Resources
Solar & wind energy
Don’t always make a constant uniform flow of energy
Need a way to store large amounts of energy
Batteries and supercapacitors
Li ion batteries are popular.
Lithium
Lightest of all metals
Has the greatest electrochemical potential and has the largest specific energy per weight.
Rechargeable batteries with lithium metal on the anode could provide extraordinarily high energy densities.
Batteries use a cathode, an anode, and an electrolyte to create electricity.
Cathode is a metal oxide
Anode consists of porous carbon.
During discharge, the ions flow from the anode to the cathode through the electrolyte and separator
Charge reverses the direction and the ions flow from the cathode to the anode.
Lithium- ion battery structure
http://batteryuniversity.com/learn/article/lithium_based_batteries
Current Applications of Nanomaterials in Batteries
silicon coated carbon nanotubes
silver-zinc battery using nanoparticles in the silver cathode
catalyst made from nitrogen-doped carbon-nanotubes
silicon nanoparticles coating a titanium disilicide lattice
silicon nanoparticles
nanowires coated with a gel
carbon nanofibers encapsulating the sulfur
mesoporous carbon nanoparticles
single atom thick graphene sheets
nano-structured lithium titanate
Figure 3: Most of the nanostructures build in anodes for Li-ion batteries.
Solar/wind- currently mostly use lead-acid batteries
Current State of Research
Current researches work on developing the cathode and anode of Li-Ion batteries
1- Cathode has high voltage (± 5V) materials
2- Anode has material with higher gravimetric energy density.
Figure 4: Metal oxide based Li-ion batteries and their properties.
http://e-mobility-nsr.eu/fileadmin/user_upload/downloads/info-pool/E-MobilityNSR_WP5._R4.pdf
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Pros/Cons of Li-ion Batteries
| Advantage | Disadvantage |
| Have high specific energy and high load capabilities with Power Cells. | Protection required, some batteries can malfunction and explode or cause fires |
| Long cycle and extend shelf-life; maintenance-free | Regulation required during transportation for large quantities |
| Simple charge algorithm and reasonably short charge times | No rapid charging possible at freezing temperatures (<0°C, <32°F) as well as other problems. |
| Low maintenance | Degrade at high temperature and when stored at high voltage |
| Lightweight | Immature technology |
Past Research on Tin Dioxide
Transition metal oxides with high theoretical capacities have been investigated as alternative anode materials.
Commercial graphite anodes used currently.
SnO2 has received special attention due to its high theoretical capacity of 1493 mAh g-1, around 4 times as high as graphite anode, and good working potential.
Equation 1 and 2, only partially reversible, 711 mA h g−1
Subsequent alloying capacity of Sn
Equation 3, highly reversible, 782 mAh g−1
Main problem with SnO2 is the fast pulverization caused by the large volume expansion, which leads to a rapid capacity decay and short cycling life.
Current/Future- Tin Dioxide as an Anode Material
There are multiple ways to make thin nanostructured tin dioxide films.
Films with columnar structures were created using the combustion chemical vapor deposition method.
The electrode showed excellent electrochemical properties:
had high capacity retention and good rate capability.
A tin dioxide nanoparticle hybrid enclosed by a Mesoporous carbon structure provided high surface area.
Research done by Zhao et al. Did both designing and synthesizing of anode
New multi-walled carbon nanotube nanostructure containing SnO2
Enhanced its electrical properties.
Combination of multi-walled carbon nanotubes with tin dioxide makes a better anode than just tin dioxide
Carbon has high electrical conductivity and provides more surface area for the reaction to happen.
Nanostructures such as tin-filled nanotubes and nanofibers have more surface area and void space to allow for volume change.
Tin Dioxide even with MWNT still suffered with large volume changes resulting in fading capacity.
We think that an anode with MWNT and a carbon coating is required to achieve smooth surface allowing for better conductivity
Limitations/Obstacles for developing
Tin Oxide (SnO2) gained the attention of engineers because of its theoretical high capacity.
Tin dioxide had large volume changes and low electrical conductivity, which will cause slow charge diffusion kinetics.
Because of lack of void space and large volume changes, pulverization of the anode occurs
Quickly fading capacity
only provides low rate capability.
http://www.ipme.ru/e-journals/RAMS/no_12711/kamali.pdf
Type of nanoparticle and characterization needed
Anode materials
Graphene is a one layer lattice made of carbon
Carbon Nanotubes
SnO2, tetrahedral structure,
SiO2 layers
Figure 5: Multiwalled carbon nanotubes (MWNTs) composite for high performance LIB’s and NIB’s.
Characterization of tin oxide nanoparticle
The fabrication of SnO2 confined within hybrid carbon structures with void space is essential to achieve excellent and long-life lithium storage performance. SnO2 nanoparticles are sandwiched between carbon structure and silicon oxide skin using a modified Stöber process synthetic approach and hydrothermal hydrolysis methods.
Figure 6: Schematic of the construction of a multiwalled nanotube tin oxide composite.
http://pubs.acs.org/doi/abs/10.1021/cm0519378
At what point of research and development of your application would you need to perform characterization?
SnO2 fabrication with hybrid carbon structures is required to achieve for long life, high capacity lithium ion storage.
Sol-gel method- use a solution and drying to create a network for metal oxides to form. Gel created during the process is then removed leaving behind the metal oxide structure.
MWNTs with diameters between 20-50 nm were bought from a chinese distributor.
Thick 40 nm layer of SiO2 applied using a modified Stöber process.
Uses solution of acid and another solution with silicon to attach itself to the MWNT.
SnO2 layer applied using Hydrothermal hydrolysis.
Another layer of SiO2 applied using Stöber process.
Carbon nanotubes created by carbonizing RF resin.
SiO2 layers removed using NaOH
Characterization tools
To measure material characterization
Scanning Electron Microscopy (SEM)
Transmission electron microscopy (TEM)
X-ray diffraction (XRD)
Brunauer-Emmett-Teller (BET)
To measure electrochemical behaviour
The cyclic voltammograms (CVs)
For synthesis
Autoclave
Processes
Stöber process- synthetic approach to prepare silica nanoparticles.
Hydrothermal hydrolysis
Sol-gel method
Figure 7: a,b) SEM and c–f) TEM images of the MWNTs@SnO 2 @C composite. Image of SnO 2 nanoparticle. g) Scanning transmission electron microscopy image and the corresponding element mapping images of h) carbon, i) tin, and j) oxygen for MWNTs@SnO 2 @C composite, demonstrating the well confined of SnO 2 nanoparticles between MWNTs and carbon layers.
What do the characterization tools measure?
SEM and TEM were used to characterize the morphology and structure of sample composites.
Detect uniform layer during the whole synthesis process.
XRD and BET used to characterize the crystalline structure of MWNTs with SnO2 , carbon composites, and to check for uniformity, pore volume, and smoothness of surface and surface area.
CVs were first carried out to investigate the electrochemical behavior of MWNTs with SnO2 and carbon coating.
Autoclave used for drying and heating. Allows for high pressure and high heat.
What information do you get from those measurements?
Measurements obtained from SEM, TEM, XRD, ET and CV’s provides accurate measurements to define the physical structure and chemical behaviour of MWNTs with SnO2.
If this battery design works it also offers a general strategy to accommodate other electrode materials
Si, Sn, metal oxides, and sulfur
large volume changes during lithium or sodium insertion/extraction
Can achieve good cycling and rate performance.
Figure 8:. Charge/discharge curves of a) OMC, b) SnO2/OMC, and c) SnO2@OMC. d) Shows the corresponding cycling performance.
Top-Down or Bottom-Up? Explain why?
Stöber process
We are applying the SiO2 onto the MWNTs. It is bottom up because we are adding material.
Hydrothermal hydrolysis
Adding SnO2 onto the MWNT and SnO2 layer
Sol-gel method
Describes our whole process.
We add materials, SnO2 and SiO2, using a solution and other methods and then use another solution to remove the gel solvent leaving selected materials behind.
http://pubs.acs.org/doi/ipdf/10.1021/acsami.6b10868
Works Cited
Zhao et al., 2017. Recent Advances in Designing and Fabricating Self-Supported Nanoelectrodes for Supercapacitors. Advanced Science.1700188
Zhao Y., Wei C., Sun S., Wang L. P., Xu Z. J. (2015). Reserving Interior Void Space for Volume Change Accommodation: An Example of Cable-Like MWNTs@SnO2@C Composite for Superior Lithium and Sodium Storage. Adv. Sci., 2: 1500097. doi: 10.1002/advs.201500097
Liu, Xianghong & Zhang, Jun & Si, Wenping & Xi, Lixia & Oswald, Shaun & Yan, Chenglin & Schmidt, Oliver. (2014). High-rate amorphous SnO2 nanomembrane anodes for Li-ion batteries with long cycling life. Nanoscale. 7. . 10.1039/C4NR04903A.
Zhang, Yuelan, et al. “Nanostructured Columnar Tin Oxide Thin Film Electrode for Lithium Ion Batteries.” Chemistry of Materials, vol. 18, no. 19, 2006, pp. 4643–4646., doi:10.1021/cm0519378.
Brinker, C. Jeffrey., and George W. Scherer. “Preface.” Sol-Gel Science: the Physics and Chemistry of Sol-Gel Processing, Elsevier Science, 2014, pp. xi-xi.
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