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A commercial lithium battery LiMn-oxide for fuel cell applications
Materials Letters 126 (2014) 85–88
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
A commercial lithium battery LiMn-oxide for fuel cell applications Bin Zhu a,b,n, Liangdong Fan a,b, Yunjun He a,c, Yufeng Zhao c, Hao Wang a,n a Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Science, Hubei University, Wuhan, Hubei 430062, China b Department of Energy Technology, Royal Institute of Technology, Stockholm, SE-10044, Sweden c Key Laboratory of Applied Chemistry, Department of Environmental and Chemical, Engineering, Yanshan University, No. 438 Hebei Street, Qinhuangdao 066004, Hebei Province, China
art ic l e i nf o
a b s t r a c t
Article history: Received 13 January 2014 Accepted 6 April 2014 Available online 13 April 2014
Hereby we report first a commercial lithium battery LiMn-oxide (LMO) positive electrode material for fuel cell applications. The obtained LMO can be used for both anode and cathode in a three-layer fuel cell, but displays low electro-catalytic activity and power output. Using a nanocomposite approach we have significantly improved the cell performance from tens mW cm 2 up to 210 mW cm 2, which is technically useful for low temperature (bellow 600 1C) ceramic fuel cells. We also constructed singlelayer fuel cell using the LMO/SDC–metal oxide composite and achieved even better performances than those for conventional anode–electrolyte–cathode three-layer fuel cells. & 2014 Elsevier B.V. All rights reserved.
Keywords: Commercial LiMn-oxide Solid oxide fuel cell Three- or single-layer fuel cell Nanocomposite SDC
1. Introduction Recent developments on solid oxide fuel cells have been carried out extensively on low temperatures operation, bellow 800 1C for using conventional yttrium stabilized zirconia, doped ceria oxide, and 300–600 1C with functional nanocomposite materials, e.g. ceria-based composites, typically, SDC (Sm0.2Ce0.8O1.9)–M2CO3 (M¼Li, Na, K) and ceria–metal oxide, such as LiZn-oxide-SDC composite [1]. NANOCOFC (Nanocomposites for advanced fuel cell technology) approach has demonstrated to be a new effective scientific methodology to develop functional nanocomposite materials to meet low temperature, 300– 600 1C, operation demands with worldwide R & D upsurge [2]. Based on NANOCOFC R&D, a breakthrough technology: an electrolyte-free fuel cell (EFFC) has been invented [3,4]. This nanocomposite approach is rationally designed to utilize the phase interface as a highway for ionic conduction as well as to realize high catalytic activity. Originated from this strategy, advanced composite ionically conductive materials, e.g., core–shell [5] and nanowire structural [6] ceria-based nanocomposite possessing exceptional ionic conductivity (over 0.1 S cm 1 above 300 1C) and unique H þ /O2 simultaneous conduction property [7,8], were developed. The NANOCOFC and EFFC approaches have successfully explored wide material feasibilities for next generation fuel cell technologies. In this work, we report to use and modify the
n Corresponding authors at: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Science, Hubei University, Wuhan, Hubei 430062, China. E-mail addresses: [email protected], [email protected] (B. Zhu).
http://dx.doi.org/10.1016/j.matlet.2014.04.011 0167-577X/& 2014 Elsevier B.V. All rights reserved.
commercially available lithium battery cathode material, LiMn-oxide, through the NANOCOFC approach for fuel cell application, with the aim to demonstrate both its technical feasibility and commercial potentials.
2. Experimental Both LiZnO-Sm0.2Ce0.8O1.9 (LZSDC) and SDC were prepared by one-step co-precipitation method. For LZSDC, stoichiometric amounts of Ce(NO3)3 6H2O and Sm(NO3)3 6H2O (Ce:Sm¼0.8:0.2 M ratio) were mixed and dissolved in deionized water to form a 0.5 M solution. LiOH/Zn(NO3)2 6H2O (Li:Zn¼1:1) 0.5 M solution was made in parallel. Then these two solutions were mixed in volume ratio of 2:1, with stirring and heating at 80 1C. Sodium carbonate solution (0.5 M) as precipitant was added into the above solution with a molar ratio, cation ions:CO3 ¼1:1.5. The precipitate was filtrated and washed four times with deionized water, followed by alcohol washing, and dried in an oven at 150 1C for 24 h to get the dried precursor, which was then sintered at 750 1C for 2 h in air. Commercial LiMn-oxide (LMO) was provided by a lithium battery industry (Duo Fu Duo Group, Advanced battery Ltd, Henan, China). The appropriate amount of the as-synthesized LZSDC was mixed with LMO in various weight ratios and ground completely. The mixture was also ground thoroughly in alcohol to enhance the interfacial contacts. Powder X-ray diffraction (XRD) patterns of as-prepared samples were recorded on a D8 Advance/PC X-ray diffractometer (Germany, Bruker Corporation), using Cu Ka as the source.
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B. Zhu et al. / Materials Letters 126 (2014) 85–88
The morphologies of the samples were examined in a JSM7100F field emission scanning electron microscope (FESEM, Japan). Fuel cells were constructed in two configurations: anode/ electrolyte/cathode three-layer and single-layer configuration. In the three-layer device (TLD), the LZSDC was the electrolyte and LMO/LZSDC were used for both anode and cathode; while the latter was directly used in the single-layer device (SLD). The details for preparation of a TLD can be found elsewhere [5]. For the SLD, the mixture of the LMO and LZSDC materials were simply pressed as one layer at the same pressure with the same diameter (13 mm) and thickness (1 mm) as the TLDs. Silver paste was coated on one surface of the green tablet and the other using nickel-foam as the current collector. The TLDs and SLDs were provided by H2 and air at its respective side for fuel cell operation. The fuel cells were measured at 550 1C with flowing hydrogen as fuel (l80–150 ml min 1) and air as the oxidant (150–300 ml min 1). The I–V curves of the cells were recorded using a programmable electronic load (IT8811, ITECH, Nanjing).
3. Results and discussion Fig. 1 displays XRD pattern of the commercial LMO. It is indexed to Li1.6Mn1.6O4 (PDF card No. 52-1841) with good crystalline.
Same to the sample prepared by two-step co-precipitation [9], the prepared LZSDC using one-step synthesis shows the same phase structure: LMO and LZSDC composite phases; On the other hand, the sample treated using alcohol grinding, shows weak diffraction reflections, indicating some disorder in crystalline or amorphous structure. The commercial LMO consists of sub-micrometer particles with crystalline faces orientation (Fig. 2a), while the LZSDC was composed by well dispersed spherical particles (Fig. 2b). The two phases are homogeneously distributed with loose contacts in the mechanically mixed sample (Fig. 2c). A significant change of the particle morphology has been observed in the alcohol grinding sample. The particles were homogenously merged with each other. This is expected to create more interfaces and close contacts for ionic transport and tripe phase boundaries, and promote the fuel cell reactions. Fig. 3a presents I–V characteristics of SLDs using commercial LMO mixed directly with the LZSDC ionic conductor in various compositions. Most compositions show the device OCVs higher than 1.0V which has demonstrated both anodic and cathodic functions of the LMO. The SLD with 40 wt% of LMO presents the highest performance. Such a composite is then subjected to alcohol grinding. The electrochemical performance of the SLD and TLD are also investigated and compared. It can be noticed that the SLD exhibited slightly higher performances than that of the TLD as shown in Fig. 3b. The above device in the SLD configuration displays the fuel cell reactions as proposed before [10]: At H2 contacting side: H2 -2H þ þ 2e At air (O2) side: 0:5O2 -2e þO2 Overall reactions: H2 þ 0:5O2 -2H þ þ O2 2H þ þ O2 -H2 O Combining the above equations, H2 þ 0:5O2 -H2 O
Fig. 1. Room temperature XRD patterns of the commercial LMO and as-prepared samples.
It can be seen clearly from Fig. 3 that in an intermediate composition between the LMO and LZSDC the device displays an optimal performance. Compared with the SLDs with the pure LZSDC and pure LMO, the SLD with LZSDC: LMO¼3: 2 gives a short circuit current density of 360 mA cm 2, one order of magnitude higher than the pure LZSDC case. This is an indication that there is a synergy effect between the ions (LZSDC) and electrons (LMO) in the two-phase composition, which is ascribed to an interfacial mechanism to cause a high ionic transport between two constituent phases. By forming two-phase composites through interaction between
Fig. 3. I–V and I–P characteristics of fuel cells at 550 1C (a) with unmodified LMO at different compositions, and (b) comparison between SLD and TLD with modified LMO at a composition of LMO:LNCZO¼ 2:3.
B. Zhu et al. / Materials Letters 126 (2014) 85–88
87
Fig. 2. SEM images of the samples (a) LMO, (b) LZSDC, (c) drying mixed LMO-LZSDC and (d) alcohol grinding LMO-LZSDC.
Li þ (from LMO) and O2 (or O ) defects formed on LZSDC nanoparticles, it builds effective paths between LMO and LZSDC for high proton and oxygen conduction as described in our previous theoretical approach study [11]. Being different from the common perovskite oxides SOFC cathode, LMO has a spinel structure, it is cheap and easily synthesized with attractive electrical properties [12], its electronic conductivity of 0.1–1 S cm 1 at a temperature range of 300 to 600 1C [13], balancing well with the ionic conductivity of LZSDC. Besides, the nanocomposite approach is used to enhance or create the interface contacts/interactions to improve the interfacial ions mobility and device performance. Instead of the dry powder mixture, we used an alcohol grinding process. As shown in Fig. 2d, there are no clear interfaces between two phase particles. Two phases are merged with each other, thus maximizing particle compact, contact and interaction. As consequences, a significant improvement in the device performances by threefold has been observed in Fig. 3b. The alcohol ground samples form a homogenous distribution and percolation networks so that ions and electrons have continuous transport paths, resulting in higher power outputs. Very recently, Dong et al. [14] studied the SMF (SrMoFe-oxide)/ ceria–carbonate composite SLD system and found that SDC with 30% SMF displayed the best device performance. They used a pure electrochemical model to describe this SLFC with some agreement with the experimental result. However, a continuous electronic network is requested to make highest power output, but not cause the short circuit. In converse, the device at this composition showed both max power output and device open circuit voltage, even higher than that using the electrolyte based three-layer fuel cell device. It is common knowledge that TLD fuel cell based on the electrolyte layer which is pure ionic conductor and acts a critical role to separate anode and cathode and transport ions without electronic short circuit. While in the SLD both electronic and ionic
materials used, in an optimized composition without short circuiting problem nor power loss either, the SLD can even display the better performance than that of the TLD. This maintains a very interesting new research subject in our ongoing research
4. Conclusion This work has first explored the commercial lithium battery positive electrode LiMn-oxide material for successful LTSOFCs and EFFCs application with significant importance both for science and commercialization. By using the nanocomposite approach to create more interfaces and particle interactions between LMO electronic phase and LZSDC ionic one, the device performances have been improved significantly for both TLD and SLD fuel cells. The SLD is even better.
Acknowledgments This work was supported by the Natural Science Foundation of China (No. 51072049 and 51202213), Hubei provincial 100 talent distinguish professor program (Hubei University), Swedish Research Council (VR, No. 621-2011-4983), EC FP7 TriSOFC project (No. 303454). References [1] [2] [3] [4] [5]
Fan L, Wang C, Chen M, Zhu B. J Power Sources 2013;234:154. Zhu B, Fan L, Lund P. Appl Energy 2013;106:163. Zhu B, Raza R, Abbas G, Singh M. Adv Funct Mater 2011;21:2465. Zhu B, Raza R, Qin H, Liu Q, Fan L. Energy Environ Sci 2011;4:2986. Wang X, Ma Y, Raza R, Muhammed M, Zhu B. Electrochem Commun 2008;10:1617. [6] Ma Y, Wang X, Li S, Toprak MS, Zhu B, Muhammed M. Adv Mater 2010;22:1640.
88
[7] [8] [9] [10]
B. Zhu et al. / Materials Letters 126 (2014) 85–88
Huang J, Mao Z, Liu Z, Wang C. Electrochem Commun 2007;9:2601. Fan L, Zhang G, Chen M, Wang C, Di J, Zhu B. Int J Electrochem Sci 2012;7:8420. Wu J, Zhu B, Mi Y, Shih S-J, Wei J, Huang Y. J Power Sources 2012;201:164. Zhu B, Lund P, Raza R, Patakangas J, Huang Q, Fan L, et al. Nano Energy 2013;2:1179.
[11] [12] [13] [14]
Zhu B, Li S, Mellander B. Electrochem Commun 2008;10:302. Davidson I, McMillan RS, Murray J, Greedan J. J Power Sources 1995;54:232. Molenda J, Kucza W. Solid State Ionics 1999;117:41. Dong X, Tian L, Li J, Zhao Y, Tian Y, Li Y. J Power Sources 2014;249:270.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
A commercial lithium battery LiMn-oxide for fuel cell applications Bin Zhu a,b,n, Liangdong Fan a,b, Yunjun He a,c, Yufeng Zhao c, Hao Wang a,n a Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Science, Hubei University, Wuhan, Hubei 430062, China b Department of Energy Technology, Royal Institute of Technology, Stockholm, SE-10044, Sweden c Key Laboratory of Applied Chemistry, Department of Environmental and Chemical, Engineering, Yanshan University, No. 438 Hebei Street, Qinhuangdao 066004, Hebei Province, China
art ic l e i nf o
a b s t r a c t
Article history: Received 13 January 2014 Accepted 6 April 2014 Available online 13 April 2014
Hereby we report first a commercial lithium battery LiMn-oxide (LMO) positive electrode material for fuel cell applications. The obtained LMO can be used for both anode and cathode in a three-layer fuel cell, but displays low electro-catalytic activity and power output. Using a nanocomposite approach we have significantly improved the cell performance from tens mW cm 2 up to 210 mW cm 2, which is technically useful for low temperature (bellow 600 1C) ceramic fuel cells. We also constructed singlelayer fuel cell using the LMO/SDC–metal oxide composite and achieved even better performances than those for conventional anode–electrolyte–cathode three-layer fuel cells. & 2014 Elsevier B.V. All rights reserved.
Keywords: Commercial LiMn-oxide Solid oxide fuel cell Three- or single-layer fuel cell Nanocomposite SDC
1. Introduction Recent developments on solid oxide fuel cells have been carried out extensively on low temperatures operation, bellow 800 1C for using conventional yttrium stabilized zirconia, doped ceria oxide, and 300–600 1C with functional nanocomposite materials, e.g. ceria-based composites, typically, SDC (Sm0.2Ce0.8O1.9)–M2CO3 (M¼Li, Na, K) and ceria–metal oxide, such as LiZn-oxide-SDC composite [1]. NANOCOFC (Nanocomposites for advanced fuel cell technology) approach has demonstrated to be a new effective scientific methodology to develop functional nanocomposite materials to meet low temperature, 300– 600 1C, operation demands with worldwide R & D upsurge [2]. Based on NANOCOFC R&D, a breakthrough technology: an electrolyte-free fuel cell (EFFC) has been invented [3,4]. This nanocomposite approach is rationally designed to utilize the phase interface as a highway for ionic conduction as well as to realize high catalytic activity. Originated from this strategy, advanced composite ionically conductive materials, e.g., core–shell [5] and nanowire structural [6] ceria-based nanocomposite possessing exceptional ionic conductivity (over 0.1 S cm 1 above 300 1C) and unique H þ /O2 simultaneous conduction property [7,8], were developed. The NANOCOFC and EFFC approaches have successfully explored wide material feasibilities for next generation fuel cell technologies. In this work, we report to use and modify the
n Corresponding authors at: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physics and Electronic Science, Hubei University, Wuhan, Hubei 430062, China. E-mail addresses: [email protected], [email protected] (B. Zhu).
http://dx.doi.org/10.1016/j.matlet.2014.04.011 0167-577X/& 2014 Elsevier B.V. All rights reserved.
commercially available lithium battery cathode material, LiMn-oxide, through the NANOCOFC approach for fuel cell application, with the aim to demonstrate both its technical feasibility and commercial potentials.
2. Experimental Both LiZnO-Sm0.2Ce0.8O1.9 (LZSDC) and SDC were prepared by one-step co-precipitation method. For LZSDC, stoichiometric amounts of Ce(NO3)3 6H2O and Sm(NO3)3 6H2O (Ce:Sm¼0.8:0.2 M ratio) were mixed and dissolved in deionized water to form a 0.5 M solution. LiOH/Zn(NO3)2 6H2O (Li:Zn¼1:1) 0.5 M solution was made in parallel. Then these two solutions were mixed in volume ratio of 2:1, with stirring and heating at 80 1C. Sodium carbonate solution (0.5 M) as precipitant was added into the above solution with a molar ratio, cation ions:CO3 ¼1:1.5. The precipitate was filtrated and washed four times with deionized water, followed by alcohol washing, and dried in an oven at 150 1C for 24 h to get the dried precursor, which was then sintered at 750 1C for 2 h in air. Commercial LiMn-oxide (LMO) was provided by a lithium battery industry (Duo Fu Duo Group, Advanced battery Ltd, Henan, China). The appropriate amount of the as-synthesized LZSDC was mixed with LMO in various weight ratios and ground completely. The mixture was also ground thoroughly in alcohol to enhance the interfacial contacts. Powder X-ray diffraction (XRD) patterns of as-prepared samples were recorded on a D8 Advance/PC X-ray diffractometer (Germany, Bruker Corporation), using Cu Ka as the source.
86
B. Zhu et al. / Materials Letters 126 (2014) 85–88
The morphologies of the samples were examined in a JSM7100F field emission scanning electron microscope (FESEM, Japan). Fuel cells were constructed in two configurations: anode/ electrolyte/cathode three-layer and single-layer configuration. In the three-layer device (TLD), the LZSDC was the electrolyte and LMO/LZSDC were used for both anode and cathode; while the latter was directly used in the single-layer device (SLD). The details for preparation of a TLD can be found elsewhere [5]. For the SLD, the mixture of the LMO and LZSDC materials were simply pressed as one layer at the same pressure with the same diameter (13 mm) and thickness (1 mm) as the TLDs. Silver paste was coated on one surface of the green tablet and the other using nickel-foam as the current collector. The TLDs and SLDs were provided by H2 and air at its respective side for fuel cell operation. The fuel cells were measured at 550 1C with flowing hydrogen as fuel (l80–150 ml min 1) and air as the oxidant (150–300 ml min 1). The I–V curves of the cells were recorded using a programmable electronic load (IT8811, ITECH, Nanjing).
3. Results and discussion Fig. 1 displays XRD pattern of the commercial LMO. It is indexed to Li1.6Mn1.6O4 (PDF card No. 52-1841) with good crystalline.
Same to the sample prepared by two-step co-precipitation [9], the prepared LZSDC using one-step synthesis shows the same phase structure: LMO and LZSDC composite phases; On the other hand, the sample treated using alcohol grinding, shows weak diffraction reflections, indicating some disorder in crystalline or amorphous structure. The commercial LMO consists of sub-micrometer particles with crystalline faces orientation (Fig. 2a), while the LZSDC was composed by well dispersed spherical particles (Fig. 2b). The two phases are homogeneously distributed with loose contacts in the mechanically mixed sample (Fig. 2c). A significant change of the particle morphology has been observed in the alcohol grinding sample. The particles were homogenously merged with each other. This is expected to create more interfaces and close contacts for ionic transport and tripe phase boundaries, and promote the fuel cell reactions. Fig. 3a presents I–V characteristics of SLDs using commercial LMO mixed directly with the LZSDC ionic conductor in various compositions. Most compositions show the device OCVs higher than 1.0V which has demonstrated both anodic and cathodic functions of the LMO. The SLD with 40 wt% of LMO presents the highest performance. Such a composite is then subjected to alcohol grinding. The electrochemical performance of the SLD and TLD are also investigated and compared. It can be noticed that the SLD exhibited slightly higher performances than that of the TLD as shown in Fig. 3b. The above device in the SLD configuration displays the fuel cell reactions as proposed before [10]: At H2 contacting side: H2 -2H þ þ 2e At air (O2) side: 0:5O2 -2e þO2 Overall reactions: H2 þ 0:5O2 -2H þ þ O2 2H þ þ O2 -H2 O Combining the above equations, H2 þ 0:5O2 -H2 O
Fig. 1. Room temperature XRD patterns of the commercial LMO and as-prepared samples.
It can be seen clearly from Fig. 3 that in an intermediate composition between the LMO and LZSDC the device displays an optimal performance. Compared with the SLDs with the pure LZSDC and pure LMO, the SLD with LZSDC: LMO¼3: 2 gives a short circuit current density of 360 mA cm 2, one order of magnitude higher than the pure LZSDC case. This is an indication that there is a synergy effect between the ions (LZSDC) and electrons (LMO) in the two-phase composition, which is ascribed to an interfacial mechanism to cause a high ionic transport between two constituent phases. By forming two-phase composites through interaction between
Fig. 3. I–V and I–P characteristics of fuel cells at 550 1C (a) with unmodified LMO at different compositions, and (b) comparison between SLD and TLD with modified LMO at a composition of LMO:LNCZO¼ 2:3.
B. Zhu et al. / Materials Letters 126 (2014) 85–88
87
Fig. 2. SEM images of the samples (a) LMO, (b) LZSDC, (c) drying mixed LMO-LZSDC and (d) alcohol grinding LMO-LZSDC.
Li þ (from LMO) and O2 (or O ) defects formed on LZSDC nanoparticles, it builds effective paths between LMO and LZSDC for high proton and oxygen conduction as described in our previous theoretical approach study [11]. Being different from the common perovskite oxides SOFC cathode, LMO has a spinel structure, it is cheap and easily synthesized with attractive electrical properties [12], its electronic conductivity of 0.1–1 S cm 1 at a temperature range of 300 to 600 1C [13], balancing well with the ionic conductivity of LZSDC. Besides, the nanocomposite approach is used to enhance or create the interface contacts/interactions to improve the interfacial ions mobility and device performance. Instead of the dry powder mixture, we used an alcohol grinding process. As shown in Fig. 2d, there are no clear interfaces between two phase particles. Two phases are merged with each other, thus maximizing particle compact, contact and interaction. As consequences, a significant improvement in the device performances by threefold has been observed in Fig. 3b. The alcohol ground samples form a homogenous distribution and percolation networks so that ions and electrons have continuous transport paths, resulting in higher power outputs. Very recently, Dong et al. [14] studied the SMF (SrMoFe-oxide)/ ceria–carbonate composite SLD system and found that SDC with 30% SMF displayed the best device performance. They used a pure electrochemical model to describe this SLFC with some agreement with the experimental result. However, a continuous electronic network is requested to make highest power output, but not cause the short circuit. In converse, the device at this composition showed both max power output and device open circuit voltage, even higher than that using the electrolyte based three-layer fuel cell device. It is common knowledge that TLD fuel cell based on the electrolyte layer which is pure ionic conductor and acts a critical role to separate anode and cathode and transport ions without electronic short circuit. While in the SLD both electronic and ionic
materials used, in an optimized composition without short circuiting problem nor power loss either, the SLD can even display the better performance than that of the TLD. This maintains a very interesting new research subject in our ongoing research
4. Conclusion This work has first explored the commercial lithium battery positive electrode LiMn-oxide material for successful LTSOFCs and EFFCs application with significant importance both for science and commercialization. By using the nanocomposite approach to create more interfaces and particle interactions between LMO electronic phase and LZSDC ionic one, the device performances have been improved significantly for both TLD and SLD fuel cells. The SLD is even better.
Acknowledgments This work was supported by the Natural Science Foundation of China (No. 51072049 and 51202213), Hubei provincial 100 talent distinguish professor program (Hubei University), Swedish Research Council (VR, No. 621-2011-4983), EC FP7 TriSOFC project (No. 303454). References [1] [2] [3] [4] [5]
Fan L, Wang C, Chen M, Zhu B. J Power Sources 2013;234:154. Zhu B, Fan L, Lund P. Appl Energy 2013;106:163. Zhu B, Raza R, Abbas G, Singh M. Adv Funct Mater 2011;21:2465. Zhu B, Raza R, Qin H, Liu Q, Fan L. Energy Environ Sci 2011;4:2986. Wang X, Ma Y, Raza R, Muhammed M, Zhu B. Electrochem Commun 2008;10:1617. [6] Ma Y, Wang X, Li S, Toprak MS, Zhu B, Muhammed M. Adv Mater 2010;22:1640.
88
[7] [8] [9] [10]
B. Zhu et al. / Materials Letters 126 (2014) 85–88
Huang J, Mao Z, Liu Z, Wang C. Electrochem Commun 2007;9:2601. Fan L, Zhang G, Chen M, Wang C, Di J, Zhu B. Int J Electrochem Sci 2012;7:8420. Wu J, Zhu B, Mi Y, Shih S-J, Wei J, Huang Y. J Power Sources 2012;201:164. Zhu B, Lund P, Raza R, Patakangas J, Huang Q, Fan L, et al. Nano Energy 2013;2:1179.
[11] [12] [13] [14]
Zhu B, Li S, Mellander B. Electrochem Commun 2008;10:302. Davidson I, McMillan RS, Murray J, Greedan J. J Power Sources 1995;54:232. Molenda J, Kucza W. Solid State Ionics 1999;117:41. Dong X, Tian L, Li J, Zhao Y, Tian Y, Li Y. J Power Sources 2014;249:270.