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CN4218R PARTICLE TECHNOLOGY FUNDAMENTALS AND APPLICATIONS

CN4218R PARTICLE TECHNOLOGY FUNDAMENTALS AND APPLICATIONS Titanium Dioxide Nanoparticles (Battery) - Energy and environmental applications. Group 4 Darren Lim ZiJie Goh Dai Mei Lum Chun Fai (Jeral) Nicholas Chua Boon Leong. Main Article.

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CN4218R PARTICLE TECHNOLOGY FUNDAMENTALS AND APPLICATIONS

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  1. CN4218R PARTICLE TECHNOLOGY FUNDAMENTALS AND APPLICATIONS Titanium Dioxide Nanoparticles (Battery) - Energy and environmental applications Group 4 Darren Lim ZiJie Goh Dai Mei Lum Chun Fai (Jeral) Nicholas Chua Boon Leong

  2. Main Article Zhang. P., Li. A., & Gong. JL. (2015). Hollow spherical titanium dioxide nanoparticles for energy and environmental applications.Particuology, 22, 13-23, October 2015. https://www-sciencedirect-com.libproxy1.nus.edu.sg/science/article/pii/S1674200115000887

  3. Introduction Uses of TiO2 in energy and environmental applications Synthesis methods for hollow spherical TiO2 nanoparticles Performance in batteries Future design and innovative thinking Summary Outline

  4. Introduction • The use of TiO2 in energy and environmental applications → Batteries • Methods were proposed to further improve performance of TiO2 in batteries • Controlling size and morphology • Different types of TiO2 hollow sphere structures with different synthesis methods

  5. Gap/Problems • First Li Battery introduced by Sony → Graphite Anodes • Drawbacks of Graphite Anodes: • Lithium Dendrites formation • Restricted to low temperatures while electric vehicles charge/discharge over a wide range of temperature

  6. Uses of TiO2 in Batteries (Why TiO2?) • TiO2 as a Anode material • Advantages of TiO2 Anode: • Greater structural stability • Reduced Lithium Dendrite formation • Roadblock: • Low theoretical reversible capacity of TiO2

  7. Phases of TiO2 • TiO2 exists as 8 known well-defined crystal structures: rutile, anatase, brookite, TiO2-B, TiO2-R, TiO2-H, TiO2-II, TiO2-III. • Increase in temperature, titania usually undergoes phase change from brookite to anatase to rutile. • Studies have shown that nanosized anatase is the most thermodynamically stable.

  8. Hollow spheres composed of anatase TiO2 nanosheets - Ding et al, 2011 • Hollow spheres with anatase TiO2 nanosheets (high proportion of exposed (001) facets) • High specific surface area (~134.9 m2/g) • High efficiency for lithium extraction, excellent capacity retention • Challenges faced with (001) facets • (001) facets have higher energy and are more unstable • Relatively lower specific surface area due to larger crystal size along [001] direction • Advantages of hollow structures • Improved reversible lithium ion storage capacity • Larger surface area

  9. Hollow spheres composed of anatase TiO2 nanosheets - Ding et al, 2011 Templating Method: Polystyrene hollow spheres (PHS) (a and b) SEM and TEM images of PHS@TiO2 hollow spheres; (c and d) SEM and TEM images of carbon@TiO2 hollow spheres treated under nitrogen (annealing step) (a and b) SEM and TEM images of TiO2 hollow spheres treated in air; (c) TEM image of near the edge of TiO2 sphere; (d) HRTEM image of a nanosheet with lattice fringe spacing of 0.19 nm in both directions.

  10. Hollow TiO2 microspheres - Zhang et al, 2011 Template-Assisted and Hydrothermal Method Polymer Microsphere Template SEM images of the hollow TiO2 microspheres formed by different hydrothermal reaction time (a: 1 h, b: 2 h, c: 12 h, and d: 48 h)

  11. TiO2 hollow spheres containing opening holes - Ding et al, 2013 • Hollow spheres with anatase TiO2 closed shell • Limitation: slow diffusion of materials into the interior of the sphere • Presence of the surface hole • Easier transportation of Li ions into and out of the interior • Increase effective reactive area, higher loading efficiency • Difficult to fabricate SEM image of TiO2 with holes

  12. TiO2 hollow spheres containing opening holes - Ding et al, 2013 Solvothermal method: Organic carboxylic acids (CA) Titanium n-butoxide (TNB) Key Factors: Length of Carbon chain of CAMolar ratio of CA/TNB Reaction time SEM images of TiO2 with holes1hr, 4hr, 8hr and (d) XRD pattern of the TiO2 hollow spheres with an opening hole.

  13. Multi-shelled TiO2 hollow spheres - Ren et al, 2014 Porous hollow multishell (thin shells) • Increases Li storage sites • Sufficient void space to buffer the volume expansion • Large interfacial surface area Carbonaceous microsphere templates TiCl4 (aq) solution, Annealing, Calcination Factors: [TiCl4] , Time, Temperature TEM micrographs showing (a) 1S-TiO2−HMS, (b) 2S-TiO2−HMS, (c) 3S-TiO2−HMS, (d) 2S-TiO2−HMS-CDS, (e) 3S-TiO2−HMS-CDS, and (f) 4S-TiO2−HMS-CDS.

  14. Performance - TiO2 hollow spheres with large amount of exposed (001) facets • When cycled at a rate of 1 C (170 mA g-1), a lithium ion battery requires 1 h to approach its full capacity. At this low current rate, a reversible capacity of 148 mA h g-1 can be retained after more than 200 charge–discharge cycles. • When the C rate is increased to 5C (850mAg1), the reversible capacity decreased to 123 mA h g-1 after 200 cycles. • Further increasing the C rate to 10 C (1700 mA g1) leads to a capacity of 98 mA h g-1.

  15. Performance - TiO2 hollow spheres with large amount of exposed (001) facets • When the current rates are 1, 2 and 5 C, the specific capacities are 189, 170, and 148 mA h g-1 respectively. Even at a current rate of as high as 10 C (1700 mA g-1), the TiO2 NSHSs are still able to deliver a reversible capacity of 91.4 mA h g-1.

  16. Performance - Mesoporous hollow TiO2 microspheres • Fixed C = 2.25 • TiO2(48)-400 demonstrates ideal cycling performance over extended cycling • After 40 cycles, • Reversible capacity (Li0.55TiO2) = 184 mAh g−1 • Reversible capacity (Li0.51TiO2) = 172 mAh g−1 Fig. Cycling performance of TiO2(48)-400 at 0.25C and 1.5C rate

  17. Performance - Mesoporous hollow TiO2 microspheres Varying C • The reversible capacity of approximately 175 mAh g-1 is obtained at 2.5C after 10 cycles • Reversible capacity reduced to about 158 and 122 mAh g-1 at the high rates of 5Cand 10C. Fig. Cycling performance of TiO2(48)-400 at high rates of 2.5C, 5C and 10C.

  18. Performance - Mesoporous hollow TiO2 microspheres • It is able to give a reversible capacity of 143 mAh g-1(Li0.43TiO2) after 40 cycles. • TiO2(48)-550 also possess excellent electrochemical performance at 0.25Cand 1.5C rate, but the reversible capacity of TiO2(48)-550 is distinctly smaller than that of TiO2(48)-400 • Positive correlation between reversible capacity of the materials and the surface area as well as pore volume. Fig. Cycling performance of TiO2(48)-550 at 1.5C rate.

  19. Performance - TiO2 hollow sphere with an opening hole Vary C from 0.2 - 4 • Both of them show relative low capacities (∼175 mA h g-11 at 0.2C for R3) compared to other methods • TiO2 particles prepared via this HA-assisted method do not possess very high crystallinity, and they are closely stacked by nanocrystals from previous TEM characterization, which is not good for electrolyte penetration into the particle interior.

  20. Performance - Multi-shelled TiO2 Hollow Microspheres • High specific capacity of 237 mAh g-1 of 3S-TiO2–HMS, after 100 cycles at a current rate of 1C • Minimal irreversible capacity loss • Capacity decreases at a rate of −9.9% after the 100th cycle • MS-TiO2−HMS possesses better structural stability than its predecessors • MS-TiO2−HMS can alleviate the strain during the charge/discharge processes • Performance higher than its predecessors • 3S-TiO2−HMS displays better performance than that of 1S- and 2S-TiO2−HMS specimens • Possesses a higher density of 10 nm nanopores, optimising the electrolyte transport and Li+ diffusion during the charge/discharge process Fig. Cycling performance (discharge capacities) at the current rate of 1 C between 1.0 and 3.0 V.

  21. Performance - Multi-shelled TiO2 Hollow Microspheres • Charge/discharge current rates are varied from 1 to 10 C. • A stable high discharge capacity of 244 mAh g-1 can be attained when the current density is switched back to 1 C. • A high rate capacity of 129 mAh g-1 is achieved at a current rate of 10 C. Fig. Cycling performance (discharge capacities) at various charge−discharge current rates of the MS-TiO2−HMS and MS-TiO2−HMS-CDS between 1.0 and 3.0 V.

  22. Performance - Multi-shelled TiO2 Hollow Microspheres Long-term cycling, C = 5 & 10 • After a long-term cycling performance of 1200 cycles, the 3S-TiO2–HMS sample demonstrated: • Current rate = 5 C, capacity retention = 159 mAh g-1 • Current rate = 10 C, capacity retention = 119 mAh g-1 Fig. Long-term cycling performance of 3S-TiO2−HMS at a charge/discharge current rate of 5 and 10 C between 1.0 and 3.0 V.

  23. Performance Summary - 1

  24. Performance Summary - 2

  25. Performance Benchmarking with Other TiO2 Anodes

  26. Summary • High surface area, thin shell structure • Maintain performance even after many cycles • Hollow spherical TiO2 therefore shows promise in many innovative applications

  27. References • Zhang. P., Li. A., & Gong. JL. (2015).Hollow spherical titanium dioxide nanoparticles for energy and environmental applications. Particuology, 22,13-23. Retrieved from https://www-sciencedirect-com.libproxy1.nus.edu.sg/science/article/pii/S1674200115000887 • Madian. M., Eychmüller. A.,& Giebeler. L. (2018). Current Advances in TiO2-Based Nanostructure Electrodes for High Performance Lithium Ion Batteries. Batteries, 4(1), 7. doi: 10.3390/batteries4010007. Retrieved from https://www.mdpi.com/2313-0105/4/1/7 • Zhang et al. (2011). Superior electrode performance of mesoporous hollow TiO2 microspheres through efficient hierarchical nanostructures. Journal of Power Sources, 196, 8618–8624. Retrieved from https://www-sciencedirect-com.libproxy1.nus.edu.sg/science/article/pii/S0378775311011189 • Ding et al. (2013). New facile synthesis of TiO2 hollow sphere with an opening hole and its enhanced rate performance in lithium-ion batteries. New J. Chem., 2013, 37, 784-789. Retrieved from https://pubs-rsc-org.libproxy1.nus.edu.sg/en/content/articlepdf/2013/nj/c2nj40956a • Ding et al. (2011). TiO2 hollow spheres with large amount of exposed (001) facets for fast reversible lithium storage. Journal of Materials Chemistry, 21, 1677-1680. Retrieved from https://www.researchgate.net/publication/235903994_TiO2_hollow_spheres_with_large_amount_of_exposed_001_facets_for_fast_reversible_lithium_storage • Ren et al. (2014). Multishelled TiO2 Hollow Microspheres as Anodes with Superior Reversible Capacity for Lithium Ion Batteries. Nano Letters, 14, 6679−6684. Retrieved from https://pubs-acs-org.libproxy1.nus.edu.sg/doi/pdf/10.1021/nl503378a

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