Sn-based Intermetallic Alloy Anode Materials for the Application of Lithium Ion Batteries

Electrochimica Acta 161 (2015) 261–268

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Sn-based Intermetallic Alloy Anode Materials for the Application of Lithium Ion Batteries P. Nithyadharseni a,b , M.V. Reddy b,c, * , B. Nalini d, M. Kalpana d,e, B.V.R. Chowdari b a

Department of Physics, Bannari Amman Institute of Technology, Sathyamangalam 638402, India Department of Physics, National University of Singapore 117542, Singapore Department of Materials Science & Engineering, National University of Singapore, 117546, Singapore d Department of Physics, Avinashilingam University for Women, Coimbatore 641043, India e Department of Physics, Karunya University, Coimbatore 641114, India b c

A R T I C L E I N F O

A B S T R A C T

Article history: Received 31 January 2015 Accepted 7 February 2015 Available online 9 February 2015

Nano-sized SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys were synthesized from metal chlorides via reductive co-precipitation method using NaBH4 as reducing agent to improve the electrochemical performance of lithium ion batteries. Phase composition and particle morphology of the compounds were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and Fourier transform infrared spectroscopy (FTIR). Thermal properties of the compounds were characterized by differential scanning calorimetry (DSC). The electrochemical performance of the alloys has been evaluated by cyclic voltammetry (CV), galvanostatic cycling (GC) and electrochemical impedance spectroscopy (EIS). Among all, SnSb:Co alloy exhibits high specific capacity retention of 580 mAh g
1 with high coulombic efficiency of 98%, at a current density of 60 mA g
1 in the potential range, 0.005–1.5 V. An electrochemical impedance spectroscopy studies was carried at various charge-discharge voltages and its fitted resistance and capacitance values are discussed. ã 2015 Elsevier Ltd. All rights reserved.

Keywords: Intermetallic alloys SnSb Nanostructured materials cyclic voltammetry Electrochemical impedance spectroscopy Lithium ion Batteries

1. Introduction Sn based anode materials have been projected as one of the most promising candidate in substitute of the already commercialized graphite, due to their high capacity, high packing density and safe thermodynamic potentials [1–3]. However, tin-based anodes have not been applied commercially due to their mechanical disintegration of active materials caused by a large volume change during charge–discharge processes [4–8]. Many attempts have been made recently to solve these problems by the use of intermetallic alloys with composite structure containing an active or inactive host matrix [9]. The use of intermetallic alloy material seems to be more effective way to control the volume changes of the alloy electrodes [10–12], where all the active components can react with Li but at different potentials in the charging/discharging process. Another promising and effective approach is to employ active/inactive alloy or intermetallics, where the inactive component can buffer the volume change and “matrix

* Corresponding author. Tel.: +65 65162607; fax: +65 67776126. E-mail addresses: [email protected], [email protected] (M.V. Reddy). http://dx.doi.org/10.1016/j.electacta.2015.02.057 0013-4686/ ã 2015 Elsevier Ltd. All rights reserved.

glue” caused by the active component and thus increases the cycling stability of electrode, such as SnSb [13–17], SnCu [18–21], SnNi [22–24], SnFe [25], SnAl [26] SnMn [27,28] and SnCo [29–31]. Therefore, the transition metal elements like Fe, Co and Ni can act as a supporting element to buffer the large volume changes and as a barrier against the aggregation of Sn and Sb into large grains during Li-ion insertion and extraction processes. Similar results had already been reported by Besenhard and co-workers [11,32]. Also transition metals like Fe, Co and Ni could increase the conductivity of the electrode [33]. On a wide search, very few reports are available on SnSb:Ni and no reports on SnSb:Fe and SnSb:Co alloy electrodes are found. Hence, the present study explores to understand the effect of matrix elements on electrochemical properties of SnSb:Fe, SnSb: Co and SnSb:Ni intermetallic alloys are synthesized by reductive co-precipitation method using NaBH4 as reducing agent. In addition, Co has high hardness and its metal matrix can increase the ductility and reduce the disintegration of alloy powders [34–36] also Ni shows inactive with Li and its excellent flexibility, electrical conductive character should be favorable for the improvement of structural stability and rate capability of alloy electrode [37,38]. Therefore, it is expected that the introduction of

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transition metals Fe, Co and Ni into Sn could increase its ductility and to buffer volume change and thus improve the electrochemical cycling stability of Sn based electrode. 2. Experimental procedure

(JCPDS #33-0118), which belongs to the space group R-3m (166)). The rhombohedral structure of SnSb alloy is not altered due to the addition of Fe, Co and Ni. SEM images shows, the particle size of SnSb:Fe and SnSb:Ni alloys are 60 nm diameter. Whereas, SnSb:Co alloy exhibits the minimal particle size of 20 nm.

SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys were prepared by simple wet chemical reductive co-precipitation method followed by our previous article [33]. Two aqueous solutions were prepared with appropriate gram molecular weights for the synthesis of Fe, Co and Ni added SnSb powder, namely solution 1 formed by SnCl2.2H2O, SbCl3.H2O, FeCl3, CoCl2, NiCl2 and sodium citrates, the ratio of Sn:Sb:M (M = Fe, Co, Ni); and solution 2 constituted of NaOH and NaBH4 (all the chemicals were AR grade – Merck). The two solutions were mixed together to obtain the required concentration of the, SnSb:Fe, SnSb:Co and SnSb:Ni alloys. The precipitates thus obtained were filtered and subsequently washed with distilled water, 0.35 M HCl, and acetone until chlorine was completely washed off and dried at ambient temperature. The structure and particle morphologies of synthesized SnSb powder were characterized by X-ray diffraction (XRD- Shimadzu 6000) and scanning electron microscopy (SEM, JEOL 6390) respectively. Raman were carried out using a Renishaw micro Raman spectrometer (Model-INVIA) with an excitation wavelength of l = 514 nm from an Ar ion laser and the Fourier Transform Infra-Red (FTIR) studies were carried out by SHIMADZU-FTIR8400S over a wavelength range of 4000–400 nm. Thermal stability (DSC) of the intermetallic alloys has been studied using PerkinElmerPyris Diamond simultaneous thermal analyzer with a resolution of 0.01 mg. The samples are taken in an aluminium pan and heated up to 900  C at a heating rate of 10  C per minute under controlled Argon atmosphere. The samples are purged using Argon atmosphere during the measurements. The electrodes fabrication was carried out by taking active materials of intermetallic alloys, polyvinylidene fluoride (PVDF) as a polymer binder and Super-P carbon black in 70:15:15 wt.%, respectively and mixing them in Nmethylpyrrolidinone (NMP) solvent for overnight. Thus electrode slurry was coated on Cu foil by using Doctor Blade technique. Then foil was cut into circular shape of 16 mm in diameter. The geometrical electrode area was around 2 cm2 and mass of active material was 2–4 mg. Coin cells were assembled in Argon gas filled glove box (MBraun, Germany) by using the fabricated electrodes as an anode, Li metal (Hohsen Corp., Japan) as counter electrode and 1 M LiPF6 in ethylene carbonate (EC) and dimethyl carbonate (DMC) (1:1 by volume, Merck Selectipur LP40) was used as the electrolyte. Thus fabricated batteries were tested at room temperature with cyclic voltammetry (CV) and galvanostatic cycling (GC) testing were performed by using Bitrode battery tester (model SCN, Bitrode, USA) and (MacPile II, Biologic, France), respectively. The cycling test were carried out in the voltage range of 0.005–1.5 V vs. Li, at the current density of 60 mA g
1 and CV was carried at the potential window of 0.005–1.5 V at a scan rate of 58 mV s
1. Electrochemical Impedance Spectroscopic (EIS) measurements of the coin cell were done with a Solartron impedance/gain-phase analyzer (model SI 1255) coupled with a potentiostat (SI 1268) at room temperature in the frequency range, 180000–0.003 Hz with an AC signal amplitude of 10 mV. The impedance data were analyzed using Z-view software (version 2.2, Scribner Assoc., Inc. U.S.A.). 3. Results and Discussion The XRD and SEM results of SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys were reported in our previous paper [33] and few results are presented here. From XRD pattern the peaks are assigned to rhombohedral structure (b-SnSb phase

Fig. 1. (a) Raman spectra, (b) FTIR spectra and (c) DSC images of SnSb:Fe, SnSb:Co and SnSb:Ni alloys.

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To elucidate the molecular environment or chemical bonds of SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys Raman spectra was carried out and are shown in Fig. 1(a). In all the compositions, the prominent peak at 448 cm
1 is attributed to the formation of SnSb alloy [39]. There is no major variation on these three compounds. Compared to the literature, the peaks are very prominent, suggested that it could be due to the lattice strain caused by Fe, Co and Ni while substituting Sn or Sb atoms. Though there are no changes observed in XRD results, lattice strain caused is evident in Raman analysis.

Fig. 2. Galvanostatic charge–discharge cycle of (a) SnSb:Fe, (b) SnSb:Co and (c) SnSb:Ni alloys.

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Fig. 1(b) shows FTIR spectrum of SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys respectively. A broad absorption band situated between 3000–3600 cm
1 is attributed to asymmetric and symmetric OH group and another one around 1600 cm
1 is assigned to O—H stretching and O—H bending vibrations respectively [40,41]. The peak at 1630 cm
1 is suppressed in the case of SnSb:Ni sample, indicating that Ni impedes the freedom of Sn and Sb atom. However, from the FTIR spectrum, the structural variation is observed due to the addition of Fe, Co and Ni is evident. The very low intensity peak observed at 2930 cm
1 is attributed to the impurities arised from the acetone. Therefore, in order to know the further changes in lattice strain thermal stability studies are carried out. Thermal stability of SnSb:Fe, SnSb:Co and SnSb:Ni alloy systems are determined using differential scanning calorimetry

Fig. 3. Cycle number vs. capacity of (a) SnSb:Fe, (b) SnSb:Co and (c) SnSb:Ni alloys.

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(DSC) analysis are shown in Fig. 1(c). A phase transition is observed at 370  C for SnSb:Fe and at 410  C for SnSb:Co and at 390  C for SnSb:Ni compositions. Thus, may be attributed to melting point of SnSb alloy [42]. The phase transition peak is sharp in the case of SnSb:Ni and moderate with SnSb:Co and mild in SnSb:Fe compositions. This is in good correlation with the lattice strains observed by Raman and FTIR analysis. Decreased phase change is also an indication of less entropy caused by Fe atoms in the SnSb:Fe arrangements. A peak at 231  C is observed in SnSb:Fe and SnSb:Co alloys, which can be easily attributed to the re-crstallization of pure tin phase [43]. Whereas in SnSb:Ni alloy, the re- crystallization of Sn phase at 231  C has completely disappeared. Galvanostatic cycling performance of charge (Li-desertion) and discharge (Li-insertion) curves of SnSb:Fe, SnSb:Co and SnSb:Ni alloys are shown in Fig. 2(a–c), cycled in the potential range of 0.005–1.5 V vs. Li, the constant current density of 60 mA g
1. In the initial discharge cycle, there is a plateau at around 1.3 V, which is an indication of solid electrolyte interface (SEI) film formation. This plateau disappeared from the second cycle onwards, indicating that a stable SEI film has been formed. Then, there is a plateau at 0.85 V, corresponding to the Li3Sb alloy formation and the slope from 0.5 to 0.3 V, represents the various formations of Li-Sn alloys [38]. The initial discharge capacity of SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys are 1680, 2630 and 1565 mAh g
1, followed by a charge capacity of 740, 1140 and 855 mAh g
1, resulting in an initial coulombic efficiencies of 44, 43 and 48% respectively. It is revealed that the initial discharge capacity values of all alloys are higher as compared to other reported alloys [37,38,44,45]. However, the compounds are suffered from a high initial irreversible capacity loss, that to be expected with the association of initial cycling process, which include the decomposition of the solvent in the electrolyte and the formation of SEI film on the

electrode surface. Thus brings structural readjustment of the electrode upon initial lithium uptake-removal, is typical of lithium-ion electrochemical processes [46,47]. Moreover, SEI formation is mainly related to smaller particle size of our compounds [36,38]. From second cycle to 10th cycle the gradual capacity fading is found in SnSb:Ni alloy, while the former two alloys exhibited rapid capacity fading which is shown in Fig. 2(a, b). The overall reversible capacity of SnSb:Fe, SnSb:Co and SnSb:Ni alloys at 10th cycles are around 680 (7.5 mol of Li/Sn), 970 (10.8 mol of Li/Sn) and 770 (8.6 mol of Li/Sn) mAh g
1, followed by a charge capacity of 666 (7.4 mol of Li/Sn), 943 (10.5 mol of Li/Sn) and 754 (8.4 mol of Li/Sn) mAh g
1, respectively. These values are approximately equal to its theoretical value of the compound. However, the reversible capacity of SnSb:Ni alloy at 10th cycles is lower than the SnSb:Co alloy and relatively higher than the SnSb:Fe alloy. The decrease in capacity fading in SnSb:Ni alloy is mainly due to inactive matrix of Ni, which can be easily buffers the volume change during cycling process. Fig. 3(a–c) shows cycle number vs. specific capacity of SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys. The overall capacity fade during cycling in SnSb:Fe alloy is lower than the SnSb:Co and SnSb: Ni intermetallic alloys. The figure shows that the SnSb:Fe, SnSb:Co and SnSb:Ni compounds deliver a specific capacity of around 530, 580 and 470 mAh g
1 at 50th cycles respectively. The calculated capacity fading at 10th cycle of SnSb:Fe, SnSb:Co and SnSb:Ni compounds are 5, 26, 11% and at 50th cycles are 35, 57, 48%, respectively. Compared to 10th and 50th cycles, the difference in capacity fading could be observed more in SnSb:Ni alloy. The overall comparison at 50th cycle, cycling stability of the SnSb:Fe alloy is increased. It is to be clear that, Fe act as an electrically conductive and also inactive matrix to support the Li-Sn alloy grains, which resulted in good cycling behavior. While, SnSb:Ni shows moderately high fading than SnSb:Fe

Fig. 4. Cyclic voltammogram of (a) first cycles for all compounds, (b, c and d) 2–6 cycles for SnSb:Fe, SnSb:Co and SnSb:Ni alloys. Scan rate: 0.058 mV/sec.

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alloy, it could be due to the excess amount of Sn shown by XRD and involves some structural variation in the Sn and Sb lattice which is observed from FTIR, Raman and thermal analysis, which resulted in mechanical pulverization of the electrode and poor cycling performance caused be large volume expansion during lithiation process of electrode [37]. However, the reversible capacity value is higher than the other reported alloys [37,46,48,49]. In contrast, SnSb:Co compound shows high reversible capacity than all the other compounds but the retention capacity at 50th cycles is only around 43%, which could be attributed to the lower amount Sn content (Sn:Co) i.e., equal amount of Sn and Co ratio is presents in the compound. But, Guo and Jianchao et. al., reported CoSnx alloy composite, in which the capacity of the compound is increased while increasing the amount Sn content in the compound [50,51]. Though, in all the compounds the capacity decay is observed upon cycling, which could be associated to the binder (PVDF). Indeed, it must be discussed, that the binder may play a crucial role in influencing the performance of high-volumechange of electrode materials. Fig. 4(a–d) shows, cyclic voltammogram plots of SnSb:Fe, SnSb: Co and SnSb:Ni intermetallic alloys. The first cycles of above these three compounds are shown in Fig. 4(a), the plateau at around 1.2 V belongs to SEI film formation and the plateau at 0.7 V corresponds to the formation of Li3Sb, when Sb phase reacts with Li+ according to Eq. (1). The peak at 0.4 V related to the formation of various formations of LixSn alloys as described in Eq. (2). In the

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reversible process shows the plateau at around 1.2 V and 0.7 V, which is belongs to de-lithiation process from Li-Sb alloy and then later from Li-Sn alloy. SnSb + 3Li+ + 3e
$ Sn + Li3Sb

(1)

Sn + yLi+ + ye
$ LiySn (0  y  4.4)

(2)

Fig. 4(b–d) shows 2–6 cycles of SnSb:Fe, SnSb:Co and SnSb:Ni alloys. In all the compounds, the cathodic peak at 1.2 V in the subsequent cycles is disappeared, which indicates the stable SEI film formation on the electrode surface. SnSb:Co and SnSb:Ni alloys showed during later cycle’s there is a significant decrease in the peak areas under lithiation and de-lithiation curves, which is the indication of appreciable capacity fading. Whereas, SnSb:Fe alloy showed both charge and discharge curves, the peak areas are increasing in the following cycles, thus promotes high capacity and good cycling response of the compound. To further explain the different electrochemical behaviors of SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys, electrochemical impedance spectroscopy was carried out. Data were recorded for fresh cell and first charge-discharge state at various voltages in the range of 0.005–1.5 V. At each voltage, during charging and discharging state the cell was exposed to a current density of 60 mA g
1 and the cells were kept rest at the given voltage for 1 h before recording the spectra. The results are plotted as Nyquist plot (Z0 vs Z00 ), and are fitted by an equivalent circuit as shown in

Fig. 5. (a) Equivalent electrical circuit, Nyquist plots for SnSb:Fe during (b) the 1st discharge and (c) the 1st charge at various voltages.

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Fig. 5(a). The equivalent circuit which was used for fitting is consisting of resistance, a constant phase element (CPEi), Warburg impedance (Ws) and intercalation capacitance (Ci) [52]. The resistance contributes to electrolyte, surface film (sf), charge transfer (ct) and bulk resistance (b). CPEi contributes to sf, double layer (dI) and b which is used instead of pure capacitor due to the composite nature of the electrode. The fitted individual impedance parameters are listed in Table 1. The Nyquist plots of SnSb:Fe alloy at various voltages respective to first charge-discharge state is shown in Fig. 5(b, c). The discharge and charge impedance plot shows a single semicircle, which is corresponds to R(sf + ct) and CPE (sf + dI). This is because the passage of current through the cell gives rise to Rct. During discharging the resistance values leads to decreasing, whereas during increase the voltage (charge cycle) the resistance values are leads to decreasing up to 1.0 V, but it started increasing afterwards. The a-values

during the first discharge and charge cycle are in the range of 0.61– 0.79. Fig. 6(a, b) shows Nyquist plot of SnSb:Co alloy, at various voltages, both charge and discharge state shows single semicircle which is resemble the spectra of SnSb:Fe alloy. The resistance values are moderately low, which indicates that good Li-ion kinetics at given voltages. Both charge-discharge states, the a-values are in the range of 0.71–0.83. In contrast, the SnSb:Ni (Fig. 6(c, d)) alloy shows, during discharging up to 0.005 V, a single semicircle is observed, whereas during increasing voltage up to 1.5 V, two semicircles are observed, which contributes to R(sf + ct) and Rb. The Rb arises due to electronic resistance of active material and ionic resistance of the electrolyte filled in the pores of the composite electrode. The R(sf + ct) and Rb values are varying from 36–58 V and 8–12 V, respectively. The a-values during the first discharge and charge cycle are in the range of 0.63–0.84. Thus, it is to be clear that the observed

Table 1 Fitted impedance values of SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys using equivalent electrical circuit. Voltage

R(sf + ct) (5 V)

CPE(sf + dI) (3 mF)

a (0.02)

Rb (3 V)

CPEb (3 mF)

Ci (F)

SnSb:Fe (1st discharge cycle) 2.9 V (fresh cell, OCV) 2.5 V 2.0 V 1.5 V 1.0 V 0.5 V 0.25 V 0.005 V

488 (Rsf) 351 310 290 213 133 124 104

30 (CPEsf) 24 30 33 31 36 35 35

0.62 0.76 0.73 0.71 0.69 0.74 0.78 0.78

– – – – – – – –

– – – – – – – –

0.02 0.01 0.01 0.01 2.90 0.20 0.39 0.97

1st charge cycle 0.25 V 0.5 V 1.0 V 1.5 V 2.0 V 2.5 V

118 108 75 81 97 123

33 31 22 23 24 29

0.79 0.73 0.62 0.61 0.61 0.69

– – – – – –

– – – – – –

0.37 0.28 0.21 0.12 0.06 0.01

SnSb:Co (1st discharge cycle) 2.9 V (fresh cell, OCV) 2.5 V 2.0 V 1.5 V 1.0 V 0.5 V 0.25 V 0.005 V

143 (Rsf) 35 25 60 51 59 38 49

20 (CPEsf) 29 25 35 27 29 21 27

0.70 0.78 0.81 0.78 0.83 0.81 0.79 0.80

– – – – – – – –

– – – – – – – –

0.01 0.01 0.02 0.04 5.79 0.66 1.80 0.01

24 21 26 33 33 32

0.78 0.75 0.71 0.75 0.74 0.75

– – – – – –

– – – – – –

1.06 0.79 0.25 0.05 0.03 0.01

26 (CPEsf) 33 31 32 29 31 24 25

0.75 0.70 0.84 0.82 0.80 0.78 0.79 0.84

– – – – – – – –

– – – – – – – –

3.04 0.01 0.01 0.03 0.08 1.01 1.68 2.25

29 28 27 21 31 28

0.78 0.75 0.79 0.79 0.63 0.62

12 11 9 8 – –

0.83 0.80 0.72 0.68 – –

1.06 1.38 0.94 0.06 0.04 0.67

1st charge cycle 0.25 V 0.5 V 1.0 V 1.5 V 2.0 V 2.5 V SnSb:Ni (1st discharge cycle) 2.9 V (fresh cell, OCV) 2.5 V 2.0 V 1.5 V 1.0 V 0.5 V 0.25 V 0.005 V 1st charge cycle 0.25 V 0.5 V 1.0 V 1.5 V 2.0 V 2.5 V

44 31 40 30 39 42

126 (Rsf) 82 28 38 48 63 51 56

53 42 36 58 78 91

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Fig. 6. Nyquist plots for SnSb:Co and SnSb:Ni alloys during (a, c) the 1st discharge and (b, d) the 1st charge at various voltages.

impedance parameters of SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys as a function of voltage are in accordance with the CV and galvanostatic cycling data. 4. Conclusions SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys were prepared by simple route co-precipitation method using NaBH4 as reducing agent have been investigated as possible anodes for lithium ion batteries. The rhombohedral structure were does not altered in all the three compounds. The very low particle size of 20 nm was observed in SnSb:Co alloys than all other. In Raman and FTIR analysis shows some lattice strain observed in all the samples and these results are well matches with thermal analysis. Galvanostatic cyclic results of SnSb:Fe, SnSb:Co and SnSb:Ni alloy exhibited high capacity of 820, 1350 and 900 mAh g
1 at second cycle. However, the little capacity fading was observed in SnSb:Fe alloy, whereas rapid capacity fading was observed in SnSb:Co and SnSb:Ni intermetallic alloys. The capacity retention of SnSb:Fe, SnSb:Co and SnSb:Ni intermetallic alloys at 50 cycles are 530, 580 and 470 mAh g
1, respectively. However, compared to literature we obtained high capacity in the initial cycles, which is the contribution of matrix elements can prevent the aggregation of metal particles and buffer the volume change of electrode in certain extent during cycling. Acknowledgement Dr. Nithya gratefully acknowledge to National University of Singapore (NUS) for partial financial support through NUS-India research initiative (NUS-IRI) fund.

References [1] M.V. Reddy, G.V. Subba Rao, B.V.R. Chowdari, Chem. Rev. 113 (2013) 5364–5457. [2] J. Wang, I.D. Raistrick, R.A. Huggins, Journal of The Electrochemical Society 133 (1986) 457–460. [3] M. Winter, J.O. Besenhard, Electrochimica Acta 45 (1999) 31–50. [4] J. Ren, X. He, L. Wang, W. Pu, C. Jiang, C. Wan, Electrochimica Acta 52 (2007) 2447–2452. [5] I.A. Courtney, J.R. Dahn, Journal of The Electrochemical Society 144 (1997) 2045–2052. [6] F.-S. Ke, L. Huang, J.-S. Cai, S.-G. Sun, Electrochimica Acta 52 (2007) 6741–6747. [7] J. Yang, Y. Takeda, N. Imanishi, O. Yamamoto, Journal of The Electrochemical Society 146 (1999) 4009–4013. [8] K. Wang, X. He, J. Ren, L. Wang, C. Jiang, C. Wan, Electrochimica Acta 52 (2006) 1221–1225. [9] A. Dailly, J. Ghanbaja, P. Willmann, D. Billaud, Electrochimica Acta 48 (2003) 977–984. [10] J. Yang, Y. Takeda, N. Imanishi, T. Ichikawa, O. Yamamoto, Journal of Power Sources 79 (1999) 220–224. [11] M. Winter, J.O. Besenhard, Electrochimica Acta 45 (1999) 31–50. [12] M. Stjerndahl, H. Bryngelsson, T. Gustafsson, J.T. Vaughey, M.M. Thackeray, K. Edström, Electrochimica Acta 52 (2007) 4947–4955. [13] A. Trifonova, M. Wachtler, M.R. Wagner, H. Schroettner, C. Mitterbauer, F. Hofer, K.C. Möller, M. Winter, J.O. Besenhard, Solid State Ionics 168 (2004) 51–59. [14] F.J. Fernández-Madrigal, P. Lavela, C.P. Vicente, J.L. Tirado, J.C. Jumas, J. OlivierFourcade, Chemistry of Materials 14 (2002) 2962–2968. [15] H. Li, L. Shi, W. Lu, X. Huang, L. Chen, Journal of The Electrochemical Society 148 (2001) A915–A922. [16] J. Yang, Y. Takeda, Q. Li, N. Imanishi, O. Yamamoto, Journal of Power Sources 90 (2000) 64–69. [17] Z. Wang, W. Tian, X. Li, J. Alloys Compd. 439 (2007) 350–354. [18] S. Sharma, L. Fransson, E. Sjöstedt, L. Nordström, B. Johansson, K. Edström, Journal of The Electrochemical Society 150 (2003) A330–A334. [19] L. Trahey, J.T. Vaughey, H.H. Kung, M.M. Thackeray, Journal of The Electrochemical Society 156 (2009) A385–A389. [20] L. Fransson, E. Nordström, K. Edström, L. Häggström, J.T. Vaughey, M.M. Thackeray, Journal of the Electrochemical Society 149 (2002) A736–A742. [21] W. Choi, J.Y. Lee, H.S. Lim, Electrochemistry Communications 6 (2004) 816–820.

268

P. Nithyadharseni et al. / Electrochimica Acta 161 (2015) 261–268

[22] I. Amadei, S. Panero, B. Scrosati, G. Cocco, L. Schiffini, Journal of Power Sources 143 (2005) 227–230. [23] J. Hassoun, S. Panero, P. Simon, P.L. Taberna, B. Scrosati, Advanced Materials 19 (2007) 1632–1635. [24] F.S. Ke, L. Huang, H.H. Jiang, H.B. Wei, F.Z. Yang, S.G. Sun, Electrochemistry Communications 9 (2007) 228–232. [25] O. Mao, R.A. Dunlap, J.R. Dahn, Journal of The Electrochemical Society 146 (1999) 405–413. [26] R. Hu, M. Zeng, C.Y.V. Li, M. Zhu, Journal of Power Sources 188 (2009) 268–273. [27] B. Philippe, A. Mahmoud, J.B. Ledeuil, M.T. Sougrati, K. Edström, R. Dedryvère, D. Gonbeau, P.E. Lippens, Electrochimica Acta 123 (2014) 72–83. [28] A. Mahmoud, M. Chamas, J.-C. Jumas, B. Philippe, R. Dedryvère, D. Gonbeau, I. Saadoune, P.-E. Lippens, Journal of Power Sources 244 (2013) 246–251. [29] D. Larcher, L.Y. Beaulieu, O. Mao, A.E. George, J.R. Dahn, Journal of The Electrochemical Society 147 (2000) 1703–1708. [30] N. Tamura, M. Fujimoto, M. Kamino, S. Fujitani, Electrochimica Acta 49 (2004) 1949–1956. [31] J. Zhu, D. Wang, T. Liu, C. Guo, Electrochim. Acta 125 (2014) 347–353. [32] M. Wachtler, M. Winter, J.O. Besenhard, Journal of Power Sources 105 (2002) 151–160. [33] P. Nithyadharseni, B. Nalini, P. Saravanan, Appl. Surf. Sci. 311 (2014) 503–507. [34] B. Luan, N. Cui, H.K. Liu, H.J. Zhao, S.X. Dou, Journal of Power Sources 55 (1995) 197–203. [35] M. Wang, H. Zhao, J. He, R. Wang, J. Chen, N. Chen, Journal of Alloys and Compounds 484 (2009) 864–869. [36] H. Guo, H. Zhao, X. Jia, X. Li, W. Qiu, Electrochimica Acta 52 (2007) 4853–4857.

[37] H. Guo, H. Zhao, X. Jia, W. Qiu, F. Cui, Mater. Res. Bull. 42 (2007) 836–843. [38] H. Guo, H. Zhao, X. Jia, J. He, W. Qiu, X. Li, J. Power Sources 174 (2007) 921–926. [39] K.H. Seng, Z.P. Guo, Z.X. Chen, H.K. Liu, Advanced Science Letters 4 (2011) 18–23. [40] W. Que, Y. Zhou, Y.L. Lam, Y.C. Chan, C.H. Kam, Thin Solid Films 358 (2000) 16–21. [41] A.V. Rao, R.R. Kalesh, G.M. Pajonk, Journal of Materials Science 38 (2003) 4407–4413. [42] Z. Wang, W. Tian, X. Liu, R. Yang, X. Li, J. Solid State Chem. 180 (2007) 3360–3365. [43] L. Simonin, U. Lafont, E.M. Kelder, Journal of Power Sources 180 (2008) 859–863. [44] F. Wang, M. Zhao, X. Song, J. Power Sources 175 (2008) 558–563. [45] M.-Y. Li, C.-L. Liu, M.-R. Shi, W.-S. Dong, Electrochim. Acta 56 (2011) 3023–3028. [46] J. Hassoun, G. Mulas, S. Panero, B. Scrosati, Electrochem. Commun. 9 (2007) 2075–2081. [47] R.A. Huggins, Journal of Power Sources 81–82 (1999) 13–19. [48] P. Chen, L. Guo, Y. Wang, J. Power Sources 222 (2013) 526–532. [49] C.J. Liu, F.H. Xue, H. Huang, X.H. Yu, C.J. Xie, M.S. Shi, G.Z. Cao, Y.G. Jung, X.-l. Dong, Electrochim. Acta 29 (2014) 93–99. [50] Guo, H. Zhao, X. Jia, W. Qiu, Rare Metals 25 (2006) 369–373. [51] J. He, H. Zhao, M. Wang, X. Jia, Materials Science and Engineering: B 171 (2010) 35–39. [52] M.V. Reddy, G.V. Subba Rao, B.V.R. Chowdari, Journal of Materials Chemistry 21 (2011) 10003–10011.