International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 04 Special Issue: 09 | Sep -2017
p-ISSN: 2395-0072
www.irjet.net
One Day International Seminar on Materials Science & Technology (ISMST 2017) 4th August 2017 Organized by
Department of Physics, Mother Teresa Women’s University, Kodaikanal, Tamilnadu, India
STRUCTURAL AND MORPHOLOGICAL OPTIMIZATIONS OF Li2FeSiO4 CATHODE MATERIAL FOR NEXT GENERATION LIBs V.Meenakshia, R.Dhanalakshmia,b, P.Rajkumara, R.Subadevia, M.Sivakumara,* #120, Energy Materials Lab, Department of Physics, Alagappa University, Karaikudi-630003. Tamil Nadu, India. bDepartment of Physics, Thiagarajar College, #139-140, Kamarajar Salai, Madurai - 625009, Tamil Nadu, India. ---------------------------------------------------------------------***--------------------------------------------------------------------a
Abstract - The optimization of Li2FeSiO4 cathode
and Co) orthosilicate group. Especially Li2FeSiO4 has provides high theoretical capacity ~333 mAhg-1 due to the extraction of more than one Li ion per formula unit and it also shows that better electrochemical properties [6]. As well as, Li2FeSiO4 has high thermal stability owing to the formation of strong Si-O bonding and is easy to synthesis. In addition to that an attempt has made to provide the tremendous benefits of silicate chemistry while explore the strong lattice stability compare to LiFePO4, due to the strong Si-O bonds in Li-Fe-Si-O [7]. However, these shows the lowering electronegativity in Si vs P will effect in a lowering of the FeII – FeIII couple. Above result suggests that these materials should have a lower band gap and therefore have a higher conductivity [1].
materials were synthesized by combination of solid state method and calcinations at high temperature, using TEOS and SiO2 as a various silicate sources. The poly anionic silicate material reveals high security, high theoretical capacity, environmental benignity with low cost, therefore is considered as one of the most capable candidate in LIBs. Li2FeSiO4 suffers from poor ionic mobility, low electronic conductivity and poor rate capability [1]. In this work, an attempt has been made to reduce the particle size of prepared samples in order to tailor its properties. The final materials have been characterized by XRD, FTIR, RAMAN, SEM and EDX analyses. The SEM analysis showed very tiny particles less than 100nm that are clubbed together on the surface of the huge particles. From the above investigations, the prepared materials can be used as one of the cathode materials for next generation LIBs.
Inappropriately, Li2FeSiO4 suggest low electronic conductivity (1.0×10-4 s cm-1) and poor rate capability (1.0×10-17 cm2s-1) due to the phenomenon of diffusion of Lithium is poor in electrochemical performance [8]. Several strategies, together with cation doping [9], carbon coating [10] and nano- architecting [11] have been adopted to overcome these difficulties. Out of these, Nanoarchitecture is an effective way to enhance the diffusion kinetics in lithiation-delithiation processing [12]. However, such nano-architecture process can promote diffusion capability and electronic conductivity, through the particle size reduction on the material surface [10]. Various methods are available for synthesis Lithium iron orthosilicate such as solid state[13], sol-gel[11], hydrothermal [14], co-precipitation[15] also. In the group of, solid state method is one of the low cost and simplest method.
Key words: TEOS, SiO2, solid state method, Li2FeSiO4, EDX.
1. INTRODUCTION In modern year, the demands for energy storage devices along with high power and energy density of lithium ion battery are considerable. Hence, the need of developments for cathode material is important in next generation lithium ion battery. High theoretical capacity, high safety, environmental acceptability and cost are also the key factors for the improving cathode materials [1-3]. Recently, polyanionic cathode materials obtained wide attention due to their high safety and cost efficiency when compared with traditional metal oxide cathodes such as LiMn2O4, LiCoO2 and LiMO2 (Ni,Fe) [4].LiFePO4 is one of the polyanionic cathode materials and it has 170mAhg-1 theoretical capacity whereas it provides poor thermal stability [5].
In this work, an attempt has been made by solid state method through various silicate sources like SiO2 and TEOS (Tetraethyl orthosilicate) with ball milling techniques. Finally, obtained samples were characterized by XRD, FT-IR, RAMAN, SEM with EDX analyses to understand the structural, morphological and compositional detail. Meanwhile, the effects of the solid
Among these polyanionic cathode materials creates considerable attention, as such as (Li2MSiO4, M=Mn, Fe © 2017, IRJET
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