研究领域
Solid state and Materials Chemistry
Energy-related devices such as batteries and fuel cells are essential in our lives. In order to develop the next generation of technologies we need more power, or better performance, at a lower environmental cost. Research into understanding the interplay between the crystal structure of new materials and their physical properties will allow us to revolutionise how we obtain and store energy.
My research approach encompasses exploratory synthesis, structural determination, physical property measurements and in situ structure and property characterisation of batteries and other devices.
Towards the next generation of batteries: Sodium-ion batteries
Lithium-ion batteries are ubiquitous in our daily lives, e.g. mobile phones and laptop computers, but their limitations have restricted wide-scale use in applications requiring higher power, e.g. electric vehicles and energy storage of renewable energy. This project will target new battery chemistries, in particular sodium-ion batteries, by developing and characterizing new electrode and electrolyte materials. We will work to develop a reliable and affordable room-temperature sodium-ion battery to provide sufficient power for large-scale energy storage from intermittent renewable power sources. Students will work on one of the following parts of a battery and test their component in idealized batteries.
Positive electrode materials
These electrodes provide the source of the sodium-ions and represent the largest cost and energy limitations for lithium-ion batteries. Here, new sodium-containing transition metal oxides, phosphates or sulfates are be synthesized and characterized to determine the relationship between crystal structure and battery performance.
Electrolytes
Sodium-ion conducting ceramics or glassy-ceramics are known to be excellent electrolytes at high temperatures (>300°C). We work towards making materials with sufficient sodium-ion conduction at room temperature.
Negative electrode materials
Negative electrodes are the least investigated component in a sodium-ion battery and the compounds used for lithium-ion batteries show poor performance in sodium-ion batteries. By developing new negative electrodes and understanding their limitations towards reversible sodium insertion/extraction we will be enable the next generation of devices. The focus of these projects are carbon based materials and the use of solid state 23Na NMR to characterise the insertion/extraction processes.
New: Tuning negative thermal expansion to produce zero thermal expansion materials
The majority of materials expand during heating via thermal expansion and this process is responsible for billions of dollars per year in maintenance, re-manufacture and replacement costs due to wear and tear on both moving parts (e.g. in aircraft gas turbines), and components that are designed to be static (e.g. in optics, coatings, electronics). If a zero thermal expansion (ZTE) material can be made, a material that neither expands nor contracts upon heating, this could dramatically reduce industrial costs. In order to achieve this, the opposite extreme of materials are considered in this project - negative thermal expansion (NTE) is a property exhibited by a small group of materials predominantly due to transverse vibrations of atom groups or cooperative rotations of units (e.g. –CN- or WO4). These materials typically feature large crystallographic voids and cations with variable oxidation states. So why not use a battery as a synthesis tool? In this project we will controllably insert Li and Na into the voids of the NTE materials, via a battery, in order to tune the cooperative rotations to produce ZTE materials.
In situ studies of materials
Investigating materials functioning in actual devices, i.e. in situ, allows the direct comparison of device performance to the atomic-level changes in the material. By manipulating the atomic-scale crystal structure of components, using a variety of synthetic techniques, improvements in device performance can be achieved, e.g. better lithium-ion batteries can be made.
In a lithium-ion battery, the charge process is characterised by the removal of lithium from the cathode, while on discharge lithium is inserted into the cathode. The cathode above features relatively small crystal-structure changes with the lithium insertion/extraction (top) making it an attractive material for commercial applications. The information on crystal-structure evolution is derived from in situ neutron powder diffraction data (bottom left) during charge/discharge cycling of the battery. The battery (bottom right) was fabricated by collaborators in Fudan University, China.
Development of new ionic conductors
Full solid-state devices are more advantageous than liquid-containing devices as they are generally safer and more robust under harsh conditions however limitations arise particularly due to the lower ionic conductivity in solids. Exploring the mechanism of ionic conduction in solids, and its relationship to factors such as temperature and dopant concentration is a method to significantly improve solid-state devices.
An example of ‘watching’ a synthesis reaction using neutron powder diffraction. Starting materials are placed on the diffractometer and the synthesis procedures are initiated while neutron powder diffraction patterns are continuously collected. For Li6PS5Cl the synthesis temperature is found to have a significant influence on the ionic conduction properties.
Structural investigations using neutron and X-ray scattering
Single crystal, solid-state and electrochemical synthetic techniques can be used to tailor-make new materials for specific applications, but critical to this process is the characterisation tools employed to elucidate the arrangement of atoms. Our use of the Australian Synchrotron and the neutron scattering facilities at ANSTO provide unparalleled insight into these materials.
近期论文
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W. M. Dose, N. Sharma*, J. C. Pramudita, J. Kimpton, E. Gonzalo, M. H. Han, T. Rojo, The crystallographic evolution of P2 Na2/3Fe0.4Mn0.6O2 electrodes during electrochemical cycling, Chemistry of Materials, Accepted August 2016.
M. Anstoetz, N. Sharma, M. Clark, L. Yee, Characterization of an oxalate-phosphate-amine metal organic framework (OPA-MOF) exhibiting properties suited for innovative applications in agriculture, Journal of Materials Science, Accepted June 2016.
C.-J. Chen, W. K. Pang, T. Mori, V. K. Peterson, N. Sharma, P.-H. Lee, S.-H. Wu, C.-C. Wang, Y.-F. Song, R.-S. Liu, The Origin of Capacity Fade in the Li2MnO3∙LiMO2 (M = Li, Ni, Co, Mn) Microsphere Positive Electrode: An Operando Neutron Diffraction and Transmission X-ray Microscopy Study. Journal of the American Chemical Society, Accepted June 2016
D. Safanama, N. Sharma, R. Prasada Rao, H. E. A. Brand and S. Adams, Structural evolution of NASICON-type Li1+xAlxGe2-x(PO4)3 using in situ synchrotron X-ray powder diffraction, Journal of Materials Chemistry A, 2016, DOI:10.1039/C6TA00402D, Accepted April 2016
N. Sharma, O. K. Al Bahri, M. H. Han, E. Gonzalo, J. C. Pramudita, T. Rojo, Comparison of the structural evolution of the O3 and P2 phases of Na2/3Fe2/3Mn1/3O2 during electrochemical cycling, Electrochimica Acta, 203, 189-197 (2016)
D. Goonetilleke, J. C. Pramudita, M. Choucair, A. Rawal, N. Sharma, Sodium insertion/extraction from single-walled and multi-walled carbon nanotubes: The differences and similarities, Journal of Power Sources, 314, 102-108 (2016)
M. H. Han, E. Gonzalo, N. Sharma, J. M. Lopez del Amo, M. Armand, M. Avdeev, T. Rojo, High Performance P2-phase Na2/3Mn0.8Fe0.1Ti0.1O2 Cathode Material for Ambient Temperature Na-Ion Batteries, Chemistry of Materials, 28, 106-116 (2016)
N. Sharma, N. Tapia-Ruiz, G. Singh, A. R. Armstrong, J. C. Pramudita, H. E. A. Brand, J. Billaud, P. G. Bruce, T. Rojo, Rate dependent performance related to crystal structure evolution of Na0.67Mn0.8Mg0.2O2 in a sodium-ion battery, Chemistry of Materials, 27, 6976−6986 (2015)
V. Palomares, P. Serras, H.E.A. Brand, T. Rojo, N. Sharma, Structural evolution of mixed valent (V3+/V4+) and V4+ sodium vanadium fluorophosphates as cathodes in sodium-ion batteries: Comparisons, overcharging and mid-term cycling, Journal of Materials Chemistry A, 3, 23017-23027 (2015)
A. Rudola, N. Sharma, P. Balaya, Introducing a 0.2 V Sodium-ion Battery Anode: The Na2Ti3O7 to Na3-xTi3O7 Pathway, Electrochemistry Communications, 61, 10-13 ( 2015)
I. Sultana, Md M. Rahman, T. Ramireddy, N. Sharma, D. Poddar, H. Zhang, Y. Chen, A. M. Glushenkov, Understanding structure-function relationship in hybrid Co3O4-Fe2O3/C lithium-ion battery electrodes, ACS Applied Materials & Interfaces, 7, 20736–20744 (2015)
D. Pontiroli, D. D’Alessio, M. Gaboardi, G. Magnani, C. Milanese, S. Duyker, V. K. Peterson, N. Sharma, M. Riccò, Ammonia-Storage in Lithium Intercalated Fullerides, Journal of Materials Chemistry A, 3, 21099–21105 (2015)
N. Sharma*, M. H. Han, J. C. Pramudita, E. Gonzalo, H. E. A. Brand, T. Rojo, A comprehensive picture of the current rate dependence on the structural evolution of P2-Na2/3Fe2/3Mn1/3O2, Journal of Materials Chemistry A, 3, 21023–21038 (2015)
J. Li, R. Petibon, S. Glazier, N. Sharma, W. K. Pang, V. K. Peterson, J. R. Dahn, In-situ Neutron Diffraction Study of a High Voltage Li(Ni0.42Mn0.42Co0.16)O2/Graphite Pouch Cell, Electrochimica Acta, 180, 234–240 (2015)
M. Gaboardi, S. Duyker, C. Milanese, G. Magnani, V. K. Peterson, D. Pontiroli, N. Sharma, M. Ricco, In Situ Neutron Powder Diffraction of Li6C60 for Hydrogen Storage, Journal of Physical Chemistry C, 119, 19715–19721 (2015)
N. Sharma*, W. K. Pang, Z. Guo, V. K. Peterson, In situ powder diffraction studies of electrode materials in rechargeable batteries, ChemSusChem, 8, 2826 – 2853 (2015)
N. Sharma*, E. Gonzalo, J. C. Pramudita, M. H. Han, H. E. A. Brand, J. N. Hart, W. K. Pang, Z. Guo, T. Rojo, The unique structural evolution of the O3-phase Na2/3Fe2/3Mn1/3O2 during high rate charge/discharge: A sodium-centred perspective, Advanced Functional Materials, 25, 4994-5005 (2015)
R. Petibon, J. Li, N. Sharma, W. K. Pang, V. K. Peterson, J. R. Dahn,The use of deuterated ethyl acetate in highly concentrated electrolyte as a low-cost solvent for in-situ neutron diffraction measurements of Li-ion battery electrodes, Electrochimica Acta, 174, 417-423 (2015)
W. K. Pang, S. Kalluri, V. K. Peterson, N. Sharma, J. Kimpton, B. Johannessen, H. K. Liu, S. X. Dou, Z. P. Guo, Interplay between electrochemistry and phase evolution of the P2-type Nax(Fe1/2Mn1/2)O2 cathode for use in sodium-ion batteries, Chemistry of Materials, 27, 3150–3158 (2015)
R.P. Rao, W. Gu, N. Sharma, V.K. Peterson, M. Avdeev, S. Adams, In situ Neutron Diffraction Monitoring of Li7La3Zr2O12 formation: Towards a Rational Synthesis of Garnet Solid Electrolytes, Chemistry of Materials, 27, 2903–2910 (2015)
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