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High rate performance of the carbon encapsulated Li4Ti5O12 for lithium ion battery
RINP 560
No. of Pages 3, Model 5G
2 February 2017 Results in Physics xxx (2017) xxx–xxx 1
Contents lists available at ScienceDirect
Results in Physics journal homepage: www.journals.elsevier.com/results-in-physics
2
Microarticle
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High rate performance of the carbon encapsulated Li4Ti5O12 for lithium ion battery
8
Qi Cheng 1, Shun Tang 1, Jiyuan Liang, Jinxing Zhao, Qian Lan, Chang Liu, Yuan-Cheng Cao ⇑
9 10 12 11 13 1 2 5 7 16 17 18 19 20 21 22 23 24 25 26
Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056, China
a r t i c l e
i n f o
Article history: Received 14 January 2017 Received in revised form 29 January 2017 Accepted 29 January 2017 Available online xxxx Keywords: Li-ion batteries Rate performance Carbon materials Li4Ti5O12 anode
a b s t r a c t Li4Ti5O12 (LTO) is attractive alternative anode material with excellent cyclic performance and high rate after coating modifications of the conductive materials. Anatase TiO2 and glucose were applied of the synthesis of the carbon coated LTO (C@LTO). XRD results showed that all the major diffractions from the spinel structure of LTO can be found in the C@LTO such as (1 1 1), (3 1 1), (4 0 0) but there are no observations of the Carbon diffraction peaks. Electrochemical Impedance Spectroscopy (EIS) data shows C@LTO resistance was nearly half of the LTO value. Rate performance showed that capacity of C@LTO was higher than that of the pure LTO from 0.1 C, 0.2 C, 1 C, 2 C, 5 C and 10 C, which indicates that this is a promising approach to prepare the high performance LTO anode. Ó 2017 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
28 29 30 31 32 33 34 35 36 37 38
39 40
Introduction
41
Lithium ion batteries (LIBs) have gained great success and attentions from portable devices to large electric vehicles (LEVs) and smart grid since last decades [1–3]. The development of high rate Li-ion batteries is essential for most battery applications, particularly in high safety, long cycle life and large capacity electrodes materials [4–8]. The current graphite based Li-ion batteries are limited by the poor rate performance and cycle life, and serious safety issues which involve the solid electrolyte interphase film (SEI) [9–11]. Therefore, researchers are exploring the SEI free anode materials which allow the electrodes tolerate the high current in charge/discharge, in order to overcome the rate and safety issues in the LIBs [10–14]. Li4Ti5O12 (LTO) related anode materials, as alternative electrode material to graphitic carbon, has the promising properties in LIBs and shows excellent cyclic performance and high rate for large power applications [12–16]. For example, the LTO anode exhibits flat and comprehensively high potentials at 1.5 V (vs Li/Li+) and shows excellent cycle life due to negligible volume change [12– 14]; LTO anodes also show very good thermal stability and high decomposition temperature, which allow them to be applicable in wider operation temperature [14]. However, LTO related electrodes also show several problems such as gassing problem during
42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62
⇑ Corresponding author. 1
E-mail address: [email protected] (Y.-C. Cao). These authors contributed equally to this work.
charging/discharging cycles, and swelling at storage, the low electronic conductivity and Li-diffusion coefficient [11–15]. These drawbacks lead to insufficient performance at high charge/discharge rates, and potential safety hazards release [10,12,15]. Here in this article, the carbon encapsulation strategy was used to increase the electronic conductivity by improving the transport properties of the material through the carbon coating. The carbon coated LTO were successfully fabricated and found to exhibit good rate capability and good cycle life.
63
Preparation of the carbon encapsulated Li4Ti5O12 (C@ Li4Ti5O12)
72
Anatase TiO2 (particle size in 100 nm) and glucose were mixed in ethanol first and then the mixture was ball milled 2 h; after the ball mill, the mixture was treated at 600 °C in Muffle furnace for 2 h with N2 flow, and then the resultant was cooled to room temperature to obtain the black carbon encapsulated TiO2 (C@TiO2). Then the C@TiO2 was mixed with Li2CO3 (Li/Ti = 0.84, in molar ration) in ethanol, which followed by ball mill again. Then the mixture was dried in oven before 800 °C treatment in Muffle furnace for 12 h with N2 flow, then cooled to room temperature to obtain the carbon encapsulated Li4Ti5O12 (C@LTO), and the carbon content was calculated to be 5%. C@LTO, acetylene black, PVDF in weight ratio of 8:1:1 were mixed in ball mill and then N-methylpyrrolidone (NMP) was added to make the slurry coating on the Cu foil, which followed by the 120 °C oven dry for 12 h to make the electrode. Then coil cell 2032 was assembled using the Celgard 2400 as the separator.
73
http://dx.doi.org/10.1016/j.rinp.2017.01.040 2211-3797/Ó 2017 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article in press as: Cheng Q et al. High rate performance of the carbon encapsulated Li4Ti5O12 for lithium ion battery. Results Phys (2017), http://dx.doi.org/10.1016/j.rinp.2017.01.040
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No. of Pages 3, Model 5G
2 February 2017
131
Conclusions
132
144
Generally, the organic carbon sources such as glucose can be used in the synthesis of carbon encapsulated LTO composite materials to produce highly purity LTO in good quality. There are no observations of the Carbon is in relatively low content thus there are no diffraction peaks in the XRD observations. Conductive carbon coating at the surface of the LTO reduces of the charge transfer resistance which makes it favourite for the electron and Li+ ions transportation as the result of the redox coupling effect and large interfacial area of the resultant material. Therefore, C@LTO is expected to have advantages such as electroactive interface for transfer of Li+ during charge/discharge, and the enhanced electronic conductivity due to inner and outer surface-coating with conductive carbon thin layers.
145
Acknowledgement
146
This project was supported by the Scientific Research Initial funding for the advanced talent of Janghan University (08010001,
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The XRD patterns of the as-synthesized C@LTO were showed in Fig. 1. For comparing, the standard LTO crystal sample was analyzed as well. From the pattern, we can see that all the major diffractions from the spinel structure of LTO can be found in the C@LTO such as (1 1 1), (3 1 1), (4 0 0), which is consist with the previous reports [10,11]. There are no observations of the Carbon diffraction peaks in the results, due the relatively low content of the carbon in the composite material. These results indicate that the synthesis method and conditions in this study can produce highly purity LTO in good quality. Electrochemical Impedance Spectroscopy (EIS) analysis was carried out for the C@LTO and standard sample (LTO), which was showed in Fig. 2. In the EIS plot, we can see that both these two spectroscopes show semicircle which can be divided into two depressed circles at high and medium frequency, respectively. The high frequencies semicircle indicates the charge transfer resistance on the C@LTO material. The data shows LTO resistance was nearly twice of the C@LTO value. The results indicate that C@LTO reduces the charge transfer resistance. We hypothesize that the reduce of the resistance is attributed to conductive carbon coating at the surface of the LTO. Fig. 3 shows the comparison of the rate capability of pure LTO and C@LTO composite at various rates in first 35 cycles. Capacity of C@LTO was higher than that of the pure LTO from 0.1 C, 0.2 C, 1 C, 2 C, 5 C and 10 C, which is might be contributed from the carbon. We can see that in the high rate of 10 C, the capacity fading is negligible due the zero-strain structure of the LTO crystals. The C@LTO anode possesses conductive surface which make it favourite for the electron and Li+ ions transportation as the result of the redox coupling effect and large interfacial area of the resultant material. Therefore, comparing to the pure LTO anode material, C@LTO is expected to have advantages such as electroactive interface for transfer of Li+ during charge/discharge, and the enhanced electronic conductivity due to inner and outer surface-coating with conductive carbon thin layers.
93
(333)
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92
(400)
Evaluation of the C@ Li4Ti5O12
91
(311)
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90
(311)
94
LAND charge and discharge tester and AutoLab station were used. A galvanostatic Li+ charge/discharge analysis was carried out in the potential range of 0.8–3.0 V vs Li/Li+. Electrochemical impedance spectroscopy measurements were performed at E = 1.55 V. The frequency range was 0.001–100 kHz under ac stimulus with 10 mV amplitude.
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Q. Cheng et al. / Results in Physics xxx (2017) xxx–xxx
Intensity / a.u.
2
C@LTO
LTO
10
20
30
40
50
60
70
80
90
2Theta / degree Fig. 1. XRD analysis of the C@LTO, comparing to the LTO standard.
Fig. 2. Electrochemical Impedance Spectroscopy analysis of the C@LTO.
Fig. 3. Rate performance of the C@LTO in various rates.
06750001), Basic Research Project of Wuhan City (2015011701011593), 4th Yellow Crane Talent Programme of Wuhan City (08010004), Hubei Province Innovative Young Research Team in Universities (T201318), The Key Project of Natural Science Foundation of Hubei Province (2014CFA098) and National High Technology Research and Development Program of China (863 Program: 2015AA033406), National Science and Technology Major Project (2016YFB0401500).
148
References
156
[1] Fang ZK et al. ACS Sustain Chem Eng 2016;4(4):1994–2003. [2] Liao CB et al. J Mater Chem A 2016;4:17215.
Please cite this article in press as: Cheng Q et al. High rate performance of the carbon encapsulated Li4Ti5O12 for lithium ion battery. Results Phys (2017), http://dx.doi.org/10.1016/j.rinp.2017.01.040
149 150 151 152 153 154 155
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RINP 560
No. of Pages 3, Model 5G
2 February 2017 Q. Cheng et al. / Results in Physics xxx (2017) xxx–xxx 159 160 161 162 163 164 165
[3] [4] [5] [6] [7] [8] [9]
Yan J et al. RSC Adv 2016;6:113228. Wang Y et al. ACS Appl Mater Interfaces 2016;8(39):26008–12. Liang J et al. J Taiwan Inst Chem Eng 2016;65:584–90. Liu F et al. Results Phys 2017;7:250–5. Liu X et al. Mater Lett 2017;187:15–9. Liu X et al. Appl Surf Sci 2017;394:183–9. Ma R et al. ACS Appl Mater Interfaces 2013;5(17):8615–27.
[10] [11] [12] [13] [14] [15] [16]
3
Verde MG et al. ACS Nano 2016;10(4):4312–21. Bae S et al. ACS Appl Mater Interfaces 2015;7:16565–72. Liu J et al. Nano Lett 2014;14(5):2597–603. Wu CL et al. J Mater Chem A 2016;4:15189. Jiang J et al. ACS Appl Mater Interfaces 2016;8(45):30926–32. Yu X et al. Nano Lett 2013;13(10):4721–7. Song K et al. J Phys Chem Lett 2014;5(8):1368–73.
166 167 168 169 170 171 172 173
Please cite this article in press as: Cheng Q et al. High rate performance of the carbon encapsulated Li4Ti5O12 for lithium ion battery. Results Phys (2017), http://dx.doi.org/10.1016/j.rinp.2017.01.040
No. of Pages 3, Model 5G
2 February 2017 Results in Physics xxx (2017) xxx–xxx 1
Contents lists available at ScienceDirect
Results in Physics journal homepage: www.journals.elsevier.com/results-in-physics
2
Microarticle
6 4 7 5
High rate performance of the carbon encapsulated Li4Ti5O12 for lithium ion battery
8
Qi Cheng 1, Shun Tang 1, Jiyuan Liang, Jinxing Zhao, Qian Lan, Chang Liu, Yuan-Cheng Cao ⇑
9 10 12 11 13 1 2 5 7 16 17 18 19 20 21 22 23 24 25 26
Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056, China
a r t i c l e
i n f o
Article history: Received 14 January 2017 Received in revised form 29 January 2017 Accepted 29 January 2017 Available online xxxx Keywords: Li-ion batteries Rate performance Carbon materials Li4Ti5O12 anode
a b s t r a c t Li4Ti5O12 (LTO) is attractive alternative anode material with excellent cyclic performance and high rate after coating modifications of the conductive materials. Anatase TiO2 and glucose were applied of the synthesis of the carbon coated LTO (C@LTO). XRD results showed that all the major diffractions from the spinel structure of LTO can be found in the C@LTO such as (1 1 1), (3 1 1), (4 0 0) but there are no observations of the Carbon diffraction peaks. Electrochemical Impedance Spectroscopy (EIS) data shows C@LTO resistance was nearly half of the LTO value. Rate performance showed that capacity of C@LTO was higher than that of the pure LTO from 0.1 C, 0.2 C, 1 C, 2 C, 5 C and 10 C, which indicates that this is a promising approach to prepare the high performance LTO anode. Ó 2017 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
28 29 30 31 32 33 34 35 36 37 38
39 40
Introduction
41
Lithium ion batteries (LIBs) have gained great success and attentions from portable devices to large electric vehicles (LEVs) and smart grid since last decades [1–3]. The development of high rate Li-ion batteries is essential for most battery applications, particularly in high safety, long cycle life and large capacity electrodes materials [4–8]. The current graphite based Li-ion batteries are limited by the poor rate performance and cycle life, and serious safety issues which involve the solid electrolyte interphase film (SEI) [9–11]. Therefore, researchers are exploring the SEI free anode materials which allow the electrodes tolerate the high current in charge/discharge, in order to overcome the rate and safety issues in the LIBs [10–14]. Li4Ti5O12 (LTO) related anode materials, as alternative electrode material to graphitic carbon, has the promising properties in LIBs and shows excellent cyclic performance and high rate for large power applications [12–16]. For example, the LTO anode exhibits flat and comprehensively high potentials at 1.5 V (vs Li/Li+) and shows excellent cycle life due to negligible volume change [12– 14]; LTO anodes also show very good thermal stability and high decomposition temperature, which allow them to be applicable in wider operation temperature [14]. However, LTO related electrodes also show several problems such as gassing problem during
42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62
⇑ Corresponding author. 1
E-mail address: [email protected] (Y.-C. Cao). These authors contributed equally to this work.
charging/discharging cycles, and swelling at storage, the low electronic conductivity and Li-diffusion coefficient [11–15]. These drawbacks lead to insufficient performance at high charge/discharge rates, and potential safety hazards release [10,12,15]. Here in this article, the carbon encapsulation strategy was used to increase the electronic conductivity by improving the transport properties of the material through the carbon coating. The carbon coated LTO were successfully fabricated and found to exhibit good rate capability and good cycle life.
63
Preparation of the carbon encapsulated Li4Ti5O12 (C@ Li4Ti5O12)
72
Anatase TiO2 (particle size in 100 nm) and glucose were mixed in ethanol first and then the mixture was ball milled 2 h; after the ball mill, the mixture was treated at 600 °C in Muffle furnace for 2 h with N2 flow, and then the resultant was cooled to room temperature to obtain the black carbon encapsulated TiO2 (C@TiO2). Then the C@TiO2 was mixed with Li2CO3 (Li/Ti = 0.84, in molar ration) in ethanol, which followed by ball mill again. Then the mixture was dried in oven before 800 °C treatment in Muffle furnace for 12 h with N2 flow, then cooled to room temperature to obtain the carbon encapsulated Li4Ti5O12 (C@LTO), and the carbon content was calculated to be 5%. C@LTO, acetylene black, PVDF in weight ratio of 8:1:1 were mixed in ball mill and then N-methylpyrrolidone (NMP) was added to make the slurry coating on the Cu foil, which followed by the 120 °C oven dry for 12 h to make the electrode. Then coil cell 2032 was assembled using the Celgard 2400 as the separator.
73
http://dx.doi.org/10.1016/j.rinp.2017.01.040 2211-3797/Ó 2017 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article in press as: Cheng Q et al. High rate performance of the carbon encapsulated Li4Ti5O12 for lithium ion battery. Results Phys (2017), http://dx.doi.org/10.1016/j.rinp.2017.01.040
64 65 66 67 68 69 70 71
74 75 76 77 78 79 80 81 82 83 84 85 86 87 88
RINP 560
No. of Pages 3, Model 5G
2 February 2017
131
Conclusions
132
144
Generally, the organic carbon sources such as glucose can be used in the synthesis of carbon encapsulated LTO composite materials to produce highly purity LTO in good quality. There are no observations of the Carbon is in relatively low content thus there are no diffraction peaks in the XRD observations. Conductive carbon coating at the surface of the LTO reduces of the charge transfer resistance which makes it favourite for the electron and Li+ ions transportation as the result of the redox coupling effect and large interfacial area of the resultant material. Therefore, C@LTO is expected to have advantages such as electroactive interface for transfer of Li+ during charge/discharge, and the enhanced electronic conductivity due to inner and outer surface-coating with conductive carbon thin layers.
145
Acknowledgement
146
This project was supported by the Scientific Research Initial funding for the advanced talent of Janghan University (08010001,
97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129
133 134 135 136 137 138 139 140 141 142 143
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The XRD patterns of the as-synthesized C@LTO were showed in Fig. 1. For comparing, the standard LTO crystal sample was analyzed as well. From the pattern, we can see that all the major diffractions from the spinel structure of LTO can be found in the C@LTO such as (1 1 1), (3 1 1), (4 0 0), which is consist with the previous reports [10,11]. There are no observations of the Carbon diffraction peaks in the results, due the relatively low content of the carbon in the composite material. These results indicate that the synthesis method and conditions in this study can produce highly purity LTO in good quality. Electrochemical Impedance Spectroscopy (EIS) analysis was carried out for the C@LTO and standard sample (LTO), which was showed in Fig. 2. In the EIS plot, we can see that both these two spectroscopes show semicircle which can be divided into two depressed circles at high and medium frequency, respectively. The high frequencies semicircle indicates the charge transfer resistance on the C@LTO material. The data shows LTO resistance was nearly twice of the C@LTO value. The results indicate that C@LTO reduces the charge transfer resistance. We hypothesize that the reduce of the resistance is attributed to conductive carbon coating at the surface of the LTO. Fig. 3 shows the comparison of the rate capability of pure LTO and C@LTO composite at various rates in first 35 cycles. Capacity of C@LTO was higher than that of the pure LTO from 0.1 C, 0.2 C, 1 C, 2 C, 5 C and 10 C, which is might be contributed from the carbon. We can see that in the high rate of 10 C, the capacity fading is negligible due the zero-strain structure of the LTO crystals. The C@LTO anode possesses conductive surface which make it favourite for the electron and Li+ ions transportation as the result of the redox coupling effect and large interfacial area of the resultant material. Therefore, comparing to the pure LTO anode material, C@LTO is expected to have advantages such as electroactive interface for transfer of Li+ during charge/discharge, and the enhanced electronic conductivity due to inner and outer surface-coating with conductive carbon thin layers.
93
(333)
96
92
(400)
Evaluation of the C@ Li4Ti5O12
91
(311)
95
90
(311)
94
LAND charge and discharge tester and AutoLab station were used. A galvanostatic Li+ charge/discharge analysis was carried out in the potential range of 0.8–3.0 V vs Li/Li+. Electrochemical impedance spectroscopy measurements were performed at E = 1.55 V. The frequency range was 0.001–100 kHz under ac stimulus with 10 mV amplitude.
89
(111)
Q. Cheng et al. / Results in Physics xxx (2017) xxx–xxx
Intensity / a.u.
2
C@LTO
LTO
10
20
30
40
50
60
70
80
90
2Theta / degree Fig. 1. XRD analysis of the C@LTO, comparing to the LTO standard.
Fig. 2. Electrochemical Impedance Spectroscopy analysis of the C@LTO.
Fig. 3. Rate performance of the C@LTO in various rates.
06750001), Basic Research Project of Wuhan City (2015011701011593), 4th Yellow Crane Talent Programme of Wuhan City (08010004), Hubei Province Innovative Young Research Team in Universities (T201318), The Key Project of Natural Science Foundation of Hubei Province (2014CFA098) and National High Technology Research and Development Program of China (863 Program: 2015AA033406), National Science and Technology Major Project (2016YFB0401500).
148
References
156
[1] Fang ZK et al. ACS Sustain Chem Eng 2016;4(4):1994–2003. [2] Liao CB et al. J Mater Chem A 2016;4:17215.
Please cite this article in press as: Cheng Q et al. High rate performance of the carbon encapsulated Li4Ti5O12 for lithium ion battery. Results Phys (2017), http://dx.doi.org/10.1016/j.rinp.2017.01.040
149 150 151 152 153 154 155
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RINP 560
No. of Pages 3, Model 5G
2 February 2017 Q. Cheng et al. / Results in Physics xxx (2017) xxx–xxx 159 160 161 162 163 164 165
[3] [4] [5] [6] [7] [8] [9]
Yan J et al. RSC Adv 2016;6:113228. Wang Y et al. ACS Appl Mater Interfaces 2016;8(39):26008–12. Liang J et al. J Taiwan Inst Chem Eng 2016;65:584–90. Liu F et al. Results Phys 2017;7:250–5. Liu X et al. Mater Lett 2017;187:15–9. Liu X et al. Appl Surf Sci 2017;394:183–9. Ma R et al. ACS Appl Mater Interfaces 2013;5(17):8615–27.
[10] [11] [12] [13] [14] [15] [16]
3
Verde MG et al. ACS Nano 2016;10(4):4312–21. Bae S et al. ACS Appl Mater Interfaces 2015;7:16565–72. Liu J et al. Nano Lett 2014;14(5):2597–603. Wu CL et al. J Mater Chem A 2016;4:15189. Jiang J et al. ACS Appl Mater Interfaces 2016;8(45):30926–32. Yu X et al. Nano Lett 2013;13(10):4721–7. Song K et al. J Phys Chem Lett 2014;5(8):1368–73.
166 167 168 169 170 171 172 173
Please cite this article in press as: Cheng Q et al. High rate performance of the carbon encapsulated Li4Ti5O12 for lithium ion battery. Results Phys (2017), http://dx.doi.org/10.1016/j.rinp.2017.01.040