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Enhancing cycle performance of lead-carbon battery anodes by lead-doped porous carbon composite and graphite additives
Accepted Manuscript Enhancing cycle performance of lead-carbon battery anodes by lead-doped porous carbon composite and graphite additives Leying Wang, Hao Zhang, Wenfeng Zhang, Gaoping Cao, Hailei Zhao, Yusheng Yang PII: DOI: Reference:
S0167-577X(17)31019-4 http://dx.doi.org/10.1016/j.matlet.2017.06.120 MLBLUE 22832
To appear in:
Materials Letters
Received Date: Revised Date: Accepted Date:
30 March 2017 19 June 2017 28 June 2017
Please cite this article as: L. Wang, H. Zhang, W. Zhang, G. Cao, H. Zhao, Y. Yang, Enhancing cycle performance of lead-carbon battery anodes by lead-doped porous carbon composite and graphite additives, Materials Letters (2017), doi: http://dx.doi.org/10.1016/j.matlet.2017.06.120
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Enhancing cycle performance of lead-carbon battery anodes by lead-doped porous carbon composite and graphite additives Leying Wanga,b, Hao Zhangb,*, Wenfeng Zhangb, Gaoping Caob, Hailei Zhao a, Yusheng Yanga,b a
School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing
100083, P. R. China b
Research institute of Chemical Defense, Beijing 100191, P. R. China
*
Corresponding author: E-mail: [email protected] (h. zhang)
ABSTRACT By using both lead-doped porous carbon composite and graphite, a hybrid carbon additive was designed to inhibit irreversible sulfation so as to enhance the cycle performance of lead-carbon battery anodes. The synergistic action mechanism was studied. We show that the hybrid carbon additive presents a unique structure of sheets attached to porous bulk, and this structure could confine the lead particles between graphite sheet and porous carbon to independently proceed the higher-rate charge-discharge testing. The separated lead nanoparticles could effectively inhibit the hydrogen evolution induced by carbon and enhance the reversible reaction of Pb/PbSO4, which prolong the cycle life of lead-carbon batteries. Keywords: Carbon materials, Graphite, Porous carbon, Nano-lead electrodeposition, Irreversible sulfation, Lead-carbon batteries. 1. Introduction Lead-carbon batteries with carbon materials as the negative additives, have excellent cycle life under High-rate partial-state-of-charge (HRPSoC) conditions in energy storage field [1−3]. Such as carbon black or graphite could improve the cycle performance of batteries due to their high electric conductivity [4], and porous carbon materials have attracted an extensive attention owing to the abundant pore structure and good electric double-layer performance [5,6]. Recently some studies reported that the lead deposits on the surface of porous carbon additives could inhibit the hydrogen evolution, provide more directions for current distribution, and thereby effectively enhance the reversible reaction of Pb/PbSO4 [7]. Our past work first verified that the lead particles on the external surface of porous carbon could be 1
electrodeposited into the nano-sized carbon pores [8]. However, a certain number of lead particles on the external surface still grow up to form the irreversible sulfation through the high-rate cycle testing. Therefore, it is very necessary to further inhibit the accumulation of PbSO4 particles on the external surface of porous carbon. Based on different mechanisms of different carbon additives, to design a hybrid carbon additive may be an effective way to play various roles in lead-carbon battery anodes. Here, we report a hybrid carbon additive consisting of lead-doped porous carbon composite and graphite in lead-carbon battery anodes. 2. Experimental Firstly, a mesopore-dominated porous carbon was prepared by using phenolic resin as a carbon precursor and CaCO3 nanoparticles (~50 nm) as a template [9]. Secondly, the porous carbon was impregnated in 0.1 mol L−1 Pb(NO3)2 under the vacuum, and then the lead-doped porous carbon composite was obtained with the addition of 0.1 mol L−1 H2SO4 dropwise. Finally, conductive graphite (KS-15, Qingdao Tianheda Graphite Co., Ltd.) was mixed together with the composite by milling in Fig. 1(a). The pure conductive graphite, the lead-doped porous carbon composite and these hybrid samples with different mass ratios of 3:7, 5:5 and 7:3 were named CG, LPC, 3CG/7LPC, 5CG/5LPC and 7CG/3LPC, respectively. The above samples were used to prepare films (120±10 µm) as the working electrode for the electrochemical testing under a three-electrode system with a platinum plate as counter electrode, and a Hg/Hg2SO4 (Sat. K2SO4) as reference electrode. The electrolyte was 5 mol L−1 H2SO4 aqueous solution with some lead powders. The samples were used for the lead electrodeposition by the potentiostatic charging at −1.135V for 5 h (Electrochemical Testing Station, Solartron 1280Z) at room temperature. The hydrogen evolution behavior of the samples were tested by cyclic voltammetry (CV) procedures from −0.7 to −1.5 V at 1 mV s−1 in 5 mol L−1 H2SO4. The high-rate charge-discharge performance of the samples were obtained by simulating HRPSoC conditions of lead-acid batteries according to the following procedures for 200 cycles: charge at 1000 mA g−1 for 45 s (upper voltage limit of −1.2 V), rest for 5 s; discharge at 1000 mA g−1 for 30 s, rest for 5 s. The lead on the external surface of the samples 2
were characterized using a Field Emission Scanning electron microscopy (FESEM, Hitachi S4800) and Energy Dispersive Spectrometer (EDS, EMAS350). Before the 2 V simulated lead-acid batteries assembled, the above samples were separately added into the negative plates during mixing the lead paste. The cells after a full charge were discharging to 60 % SoC at 1 C10 rate. And then the HRPSoC cycle performance of the cells were tested under the following procedures: charge at 2 C10 for 90 s (upper voltage limit of 2.35 V), rest for 10 s; discharge at 2 C10 for 60 s, and rest for 10 s. The cell voltage was measured at the end of the discharge pulses, and the cycle testing was stopped when the end of cell discharge voltage fell down to 1.70 V. 3. Results and discussion The morphology of 3CG/7LPC present that PbSO4 particles were deposited on the external surface of porous carbon attached with the conductive sheet graphite in Fig. 1(b). When pure LPC were conducted to the lead electrodeposition, the PbSO4 particles were reduced to Pb particles in the shape of petals (~500 nm) in Fig. 1(c), which were further verified by the change of EDS patterns in Fig. 1(e~g). However, it’s worth noting that the Pb particles in the shape of irregular polyhedron (0.5~2 µm) were electrodeposited on the surface of both porous carbon and conductive graphite in 3CG/7LPC after lead electrodeposition in Fig. 1(d). And the size of the reduced Pb particles was larger than that of LPC, but the quantity was more than that of LPC, which reflected that CG with the high conductivity is more beneficial for the lead electrodeposition [10].
3
Fig. 1. (a) Preparation of CG/LPC hybrid samples; SEM images of (b) 3CG/7LPC, (c) LPC after Pb electrodeposition, (d) 3CG/7LPC after Pb electrodeposition; EDS patterns of (e) 3CG/7LPC, (f) LPC after Pb electrodeposition, (g) 3CG/7LPC after Pb electrodeposition. In Fig. 2(a), CG with the highest ih (−5.61 A g−1) at −1.5 V presented the much more serious hydrogen evolution behavior than 7CG/3LPC (−1.40 A g−1), 5CG/5LPC (−0.85 A g−1), 3CG/7LPC (−0.72 A g−1) and LPC (−0.17 A g−1). With the increase of the content of CG, the CG/LPC hybrid samples presented the more serious hydrogen evolution behavior. Through the lead electrodeposition, the ih at −1.5 V of CG, 7CG/3LPC, 5CG/5LPC, 3CG/7LPC and LPC were separately decreased to −0.99 A g−1, −0.68 A g−1, −0.50 A g−1, −0.42 A g−1 and −0.11 A g−1 in Fig. 2(b). This is the result of the lead electrodeposition on the surface of all samples in Fig. 1(c,d), which could inhibit the hydrogen evolution induced by carbon
due to the high hydrogen evolution overvoltage of lead particles [7,8]. The CV curves of 7CG/3LPC,
5CG/5LPC and 3CG/7LPC after the lead electrodeposition have a gentle reduction peak with Pb2+ reduced to Pb from −1.0 to −1.2 V in the charging state, and an obvious oxidation peak with Pb oxidized to Pb2+, and then to form PbSO4 from −1.0 to −0.9 V in the discharging state. By contrast, there are not obvious redox peaks in the CV curves of CG and LPC after the lead electrodeposition. This phenomenon illustrated that the CG/LPC hybrid samples, which present the unique structure of sheets attached to porous bulk, could increase the oxidation and reduction current of the reversible reaction of Pb/PbSO4. And it’s beneficial for the conversion between PbSO4 and Pb on the surface of carbon materials.
Fig. 2. CV curves of all samples from −0.7 to −1.5 V at 1 mV s−1, (a) before Pb electrodeposition, (b) after Pb electrodeposition; (c) high-rate cycling performance of all samples after Pb electrodeposition; SEM images of samples after 200 cycles’ testing, (d) LPC, (e, f) 3CG/7LPC.The hydrogen evolution behavior of all samples were compared by the specific current (ih) of CV curves at −1.5 V.
Fig. 3. HRPSoC cycling performance of the 2V simulated lead-carbon batteries; and the diagrammatic sketch of synergistic action mechanism by adding the hybrid carbon additive. The high-rate cycle performance of the CG/LPC hybrid samples declined with the increase of the content of CG, and 3CG/7LPC maintained the lower voltage platform to present the better cycle performance in Fig. 2(c). After 200 cycles’ testing, there were some blocky-shaped lead particles (~5 µm) electrodeposited on the external surface of LPC in Fig. 2d, which would still affect the reversible conversion of Pb/PbSO4, and thereby result in the irreversible sulfation through more cycles. It’s worth noting that after 200 cycles’ testing, 3CG/7LPC could still control the lead particles on the external surface of carbon under the size of 200~500 nm in Fig. 2(e,f). This phenomenon could effectively improve the cyclic reversibility of Pb/PbSO4, which lead to the better high-rate cycle performance of 3CG/7LPC in Fig. 2(c). The cycle performance of 2 V simulated lead-carbon batteries were evaluated by HRPSoC testing in Fig. 3. The blank cell without carbon additives reached the cut-off discharge voltage at 11,521 cycles. After adding 1wt.% CG, 7CG/3LPC, 5CG/5LPC, 3CG/7LPC and LPC into the negative plates, the HRPSoC cycle performance of cells were prolonged to 22,558, 33,435, 39,687, 53,993 and 44,757 cycles, respectively. The cell added by 3CG/7LPC had the best HRPSoC cycle performance,
which was in good agreement with the results tested with the three-electrode system. Due to the high conductivity and the sheet structure, CG in the hybrid additive could effectively enhance the lead electrodeposition on the external surface of porous carbon through the high-rate cycle testing. The hybrid additive with the unique structure could not only make the nano-lead particles electrodeposited into carbon pores, but also confine the lead particles on the external surface of carbon between sheets graphite and porous carbon bulk in Fig. 3. Those lead particles could be less affected by other lead particles, and thus maintain the nano-size to independently and effectively proceed the reversible reaction of Pb/PbSO4, which could effectively prolong the cycle life of lead-carbon batteries. 4. Conclusions The hybrid carbon additive was prepared by using both lead-doped porous carbon composite and graphite with different mass ratios. This hybrid carbon additive could provide a unique structure with sheets attached to porous bulk, which confine the lead particles existing between sheet graphite and porous carbon, and thereby make them less aggregation with other lead particles to independently and effectively proceed the cycle testing. By adding 1 wt.% 3CG/7LPC into the simulated lead-acid battery anode, the unique structure makes the lead particles not only electrodeposited on the internal surface of carbon with nano-size, but also most effectively restrained the accumulation on the external surface. Through much high-rate charge-discharge testing, these nano-lead particles could effectively inhibit the hydrogen evolution caused by carbon and improve the reversible reaction of Pb/PbSO4, which make the cell show excellent HRPSoC cycle performance. Acknowledgements The present study was financial supported by Beijing Nova Program (Z131109000413060) and Project of China Electric Power Research Institute (DG71-15-020). References [1] K.R. Bullock, J. Power Sources 195 (14) (2010) 4513–4519. [2] E. Ebner, D. Burow, A. Börger, M. Wark, P. Atanassova, and J. Valenciano, J. Power Sources 239 7
(2013) 483–489. [3] M. Shiomi, T. Funato, K. Nakamura, K. Takahashi, and M. Tsubota, J. Power Sources 64 (1–2) (1997) 147–152. [4] J. Valenciano, A. Sánchez, F. Trinidad, and A.F. Hollenkamp, J. Power Sources 158 (2) (2006) 851–863. [5] D. Pavlov, and P. Nikolov, J. Power Sources 242 (2013) 380–399.. [6] P.T. Moseley, D.A.J. Rand, and K. Peters, J. Power Sources 295 (2015) 268–274. [7] W. Zhang, H. Lin, H. Lu, D. Liu, J. Yin, and Z. Lin, J. Mater. Chem. A 3 (8) (2015) 4399–4404. [8] L. Wang, W. Zhang, L. Gu, Y. Gong, G. Cao, H. Zhao, Y. Yang, and H. Zhang, Electrochim. Acta 222 (2016), 376–384. [9] C. Zhao, W. Wang, Z. Yu, H. Zhang, A. Wang, and Y. Yang, J. Mater. Chem. 20 (2010) 976–980. [10] L.A. Yolshina, V.A. Yolshina, A.N. Yolshin, and S.V. Plaksin, J. Power Sources 278 (2015) 87–97.
8
Graphical abstract
Highlights
A hybrid additive consists of lead-doped porous carbon composite and graphite.
The additive with sheets attached to porous bulk inhibit irreversible sulfation.
The high-rate cycle life of lead-carbon battery is remarkably prolonged.
10
S0167-577X(17)31019-4 http://dx.doi.org/10.1016/j.matlet.2017.06.120 MLBLUE 22832
To appear in:
Materials Letters
Received Date: Revised Date: Accepted Date:
30 March 2017 19 June 2017 28 June 2017
Please cite this article as: L. Wang, H. Zhang, W. Zhang, G. Cao, H. Zhao, Y. Yang, Enhancing cycle performance of lead-carbon battery anodes by lead-doped porous carbon composite and graphite additives, Materials Letters (2017), doi: http://dx.doi.org/10.1016/j.matlet.2017.06.120
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Enhancing cycle performance of lead-carbon battery anodes by lead-doped porous carbon composite and graphite additives Leying Wanga,b, Hao Zhangb,*, Wenfeng Zhangb, Gaoping Caob, Hailei Zhao a, Yusheng Yanga,b a
School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing
100083, P. R. China b
Research institute of Chemical Defense, Beijing 100191, P. R. China
*
Corresponding author: E-mail: [email protected] (h. zhang)
ABSTRACT By using both lead-doped porous carbon composite and graphite, a hybrid carbon additive was designed to inhibit irreversible sulfation so as to enhance the cycle performance of lead-carbon battery anodes. The synergistic action mechanism was studied. We show that the hybrid carbon additive presents a unique structure of sheets attached to porous bulk, and this structure could confine the lead particles between graphite sheet and porous carbon to independently proceed the higher-rate charge-discharge testing. The separated lead nanoparticles could effectively inhibit the hydrogen evolution induced by carbon and enhance the reversible reaction of Pb/PbSO4, which prolong the cycle life of lead-carbon batteries. Keywords: Carbon materials, Graphite, Porous carbon, Nano-lead electrodeposition, Irreversible sulfation, Lead-carbon batteries. 1. Introduction Lead-carbon batteries with carbon materials as the negative additives, have excellent cycle life under High-rate partial-state-of-charge (HRPSoC) conditions in energy storage field [1−3]. Such as carbon black or graphite could improve the cycle performance of batteries due to their high electric conductivity [4], and porous carbon materials have attracted an extensive attention owing to the abundant pore structure and good electric double-layer performance [5,6]. Recently some studies reported that the lead deposits on the surface of porous carbon additives could inhibit the hydrogen evolution, provide more directions for current distribution, and thereby effectively enhance the reversible reaction of Pb/PbSO4 [7]. Our past work first verified that the lead particles on the external surface of porous carbon could be 1
electrodeposited into the nano-sized carbon pores [8]. However, a certain number of lead particles on the external surface still grow up to form the irreversible sulfation through the high-rate cycle testing. Therefore, it is very necessary to further inhibit the accumulation of PbSO4 particles on the external surface of porous carbon. Based on different mechanisms of different carbon additives, to design a hybrid carbon additive may be an effective way to play various roles in lead-carbon battery anodes. Here, we report a hybrid carbon additive consisting of lead-doped porous carbon composite and graphite in lead-carbon battery anodes. 2. Experimental Firstly, a mesopore-dominated porous carbon was prepared by using phenolic resin as a carbon precursor and CaCO3 nanoparticles (~50 nm) as a template [9]. Secondly, the porous carbon was impregnated in 0.1 mol L−1 Pb(NO3)2 under the vacuum, and then the lead-doped porous carbon composite was obtained with the addition of 0.1 mol L−1 H2SO4 dropwise. Finally, conductive graphite (KS-15, Qingdao Tianheda Graphite Co., Ltd.) was mixed together with the composite by milling in Fig. 1(a). The pure conductive graphite, the lead-doped porous carbon composite and these hybrid samples with different mass ratios of 3:7, 5:5 and 7:3 were named CG, LPC, 3CG/7LPC, 5CG/5LPC and 7CG/3LPC, respectively. The above samples were used to prepare films (120±10 µm) as the working electrode for the electrochemical testing under a three-electrode system with a platinum plate as counter electrode, and a Hg/Hg2SO4 (Sat. K2SO4) as reference electrode. The electrolyte was 5 mol L−1 H2SO4 aqueous solution with some lead powders. The samples were used for the lead electrodeposition by the potentiostatic charging at −1.135V for 5 h (Electrochemical Testing Station, Solartron 1280Z) at room temperature. The hydrogen evolution behavior of the samples were tested by cyclic voltammetry (CV) procedures from −0.7 to −1.5 V at 1 mV s−1 in 5 mol L−1 H2SO4. The high-rate charge-discharge performance of the samples were obtained by simulating HRPSoC conditions of lead-acid batteries according to the following procedures for 200 cycles: charge at 1000 mA g−1 for 45 s (upper voltage limit of −1.2 V), rest for 5 s; discharge at 1000 mA g−1 for 30 s, rest for 5 s. The lead on the external surface of the samples 2
were characterized using a Field Emission Scanning electron microscopy (FESEM, Hitachi S4800) and Energy Dispersive Spectrometer (EDS, EMAS350). Before the 2 V simulated lead-acid batteries assembled, the above samples were separately added into the negative plates during mixing the lead paste. The cells after a full charge were discharging to 60 % SoC at 1 C10 rate. And then the HRPSoC cycle performance of the cells were tested under the following procedures: charge at 2 C10 for 90 s (upper voltage limit of 2.35 V), rest for 10 s; discharge at 2 C10 for 60 s, and rest for 10 s. The cell voltage was measured at the end of the discharge pulses, and the cycle testing was stopped when the end of cell discharge voltage fell down to 1.70 V. 3. Results and discussion The morphology of 3CG/7LPC present that PbSO4 particles were deposited on the external surface of porous carbon attached with the conductive sheet graphite in Fig. 1(b). When pure LPC were conducted to the lead electrodeposition, the PbSO4 particles were reduced to Pb particles in the shape of petals (~500 nm) in Fig. 1(c), which were further verified by the change of EDS patterns in Fig. 1(e~g). However, it’s worth noting that the Pb particles in the shape of irregular polyhedron (0.5~2 µm) were electrodeposited on the surface of both porous carbon and conductive graphite in 3CG/7LPC after lead electrodeposition in Fig. 1(d). And the size of the reduced Pb particles was larger than that of LPC, but the quantity was more than that of LPC, which reflected that CG with the high conductivity is more beneficial for the lead electrodeposition [10].
3
Fig. 1. (a) Preparation of CG/LPC hybrid samples; SEM images of (b) 3CG/7LPC, (c) LPC after Pb electrodeposition, (d) 3CG/7LPC after Pb electrodeposition; EDS patterns of (e) 3CG/7LPC, (f) LPC after Pb electrodeposition, (g) 3CG/7LPC after Pb electrodeposition. In Fig. 2(a), CG with the highest ih (−5.61 A g−1) at −1.5 V presented the much more serious hydrogen evolution behavior than 7CG/3LPC (−1.40 A g−1), 5CG/5LPC (−0.85 A g−1), 3CG/7LPC (−0.72 A g−1) and LPC (−0.17 A g−1). With the increase of the content of CG, the CG/LPC hybrid samples presented the more serious hydrogen evolution behavior. Through the lead electrodeposition, the ih at −1.5 V of CG, 7CG/3LPC, 5CG/5LPC, 3CG/7LPC and LPC were separately decreased to −0.99 A g−1, −0.68 A g−1, −0.50 A g−1, −0.42 A g−1 and −0.11 A g−1 in Fig. 2(b). This is the result of the lead electrodeposition on the surface of all samples in Fig. 1(c,d), which could inhibit the hydrogen evolution induced by carbon
due to the high hydrogen evolution overvoltage of lead particles [7,8]. The CV curves of 7CG/3LPC,
5CG/5LPC and 3CG/7LPC after the lead electrodeposition have a gentle reduction peak with Pb2+ reduced to Pb from −1.0 to −1.2 V in the charging state, and an obvious oxidation peak with Pb oxidized to Pb2+, and then to form PbSO4 from −1.0 to −0.9 V in the discharging state. By contrast, there are not obvious redox peaks in the CV curves of CG and LPC after the lead electrodeposition. This phenomenon illustrated that the CG/LPC hybrid samples, which present the unique structure of sheets attached to porous bulk, could increase the oxidation and reduction current of the reversible reaction of Pb/PbSO4. And it’s beneficial for the conversion between PbSO4 and Pb on the surface of carbon materials.
Fig. 2. CV curves of all samples from −0.7 to −1.5 V at 1 mV s−1, (a) before Pb electrodeposition, (b) after Pb electrodeposition; (c) high-rate cycling performance of all samples after Pb electrodeposition; SEM images of samples after 200 cycles’ testing, (d) LPC, (e, f) 3CG/7LPC.The hydrogen evolution behavior of all samples were compared by the specific current (ih) of CV curves at −1.5 V.
Fig. 3. HRPSoC cycling performance of the 2V simulated lead-carbon batteries; and the diagrammatic sketch of synergistic action mechanism by adding the hybrid carbon additive. The high-rate cycle performance of the CG/LPC hybrid samples declined with the increase of the content of CG, and 3CG/7LPC maintained the lower voltage platform to present the better cycle performance in Fig. 2(c). After 200 cycles’ testing, there were some blocky-shaped lead particles (~5 µm) electrodeposited on the external surface of LPC in Fig. 2d, which would still affect the reversible conversion of Pb/PbSO4, and thereby result in the irreversible sulfation through more cycles. It’s worth noting that after 200 cycles’ testing, 3CG/7LPC could still control the lead particles on the external surface of carbon under the size of 200~500 nm in Fig. 2(e,f). This phenomenon could effectively improve the cyclic reversibility of Pb/PbSO4, which lead to the better high-rate cycle performance of 3CG/7LPC in Fig. 2(c). The cycle performance of 2 V simulated lead-carbon batteries were evaluated by HRPSoC testing in Fig. 3. The blank cell without carbon additives reached the cut-off discharge voltage at 11,521 cycles. After adding 1wt.% CG, 7CG/3LPC, 5CG/5LPC, 3CG/7LPC and LPC into the negative plates, the HRPSoC cycle performance of cells were prolonged to 22,558, 33,435, 39,687, 53,993 and 44,757 cycles, respectively. The cell added by 3CG/7LPC had the best HRPSoC cycle performance,
which was in good agreement with the results tested with the three-electrode system. Due to the high conductivity and the sheet structure, CG in the hybrid additive could effectively enhance the lead electrodeposition on the external surface of porous carbon through the high-rate cycle testing. The hybrid additive with the unique structure could not only make the nano-lead particles electrodeposited into carbon pores, but also confine the lead particles on the external surface of carbon between sheets graphite and porous carbon bulk in Fig. 3. Those lead particles could be less affected by other lead particles, and thus maintain the nano-size to independently and effectively proceed the reversible reaction of Pb/PbSO4, which could effectively prolong the cycle life of lead-carbon batteries. 4. Conclusions The hybrid carbon additive was prepared by using both lead-doped porous carbon composite and graphite with different mass ratios. This hybrid carbon additive could provide a unique structure with sheets attached to porous bulk, which confine the lead particles existing between sheet graphite and porous carbon, and thereby make them less aggregation with other lead particles to independently and effectively proceed the cycle testing. By adding 1 wt.% 3CG/7LPC into the simulated lead-acid battery anode, the unique structure makes the lead particles not only electrodeposited on the internal surface of carbon with nano-size, but also most effectively restrained the accumulation on the external surface. Through much high-rate charge-discharge testing, these nano-lead particles could effectively inhibit the hydrogen evolution caused by carbon and improve the reversible reaction of Pb/PbSO4, which make the cell show excellent HRPSoC cycle performance. Acknowledgements The present study was financial supported by Beijing Nova Program (Z131109000413060) and Project of China Electric Power Research Institute (DG71-15-020). References [1] K.R. Bullock, J. Power Sources 195 (14) (2010) 4513–4519. [2] E. Ebner, D. Burow, A. Börger, M. Wark, P. Atanassova, and J. Valenciano, J. Power Sources 239 7
(2013) 483–489. [3] M. Shiomi, T. Funato, K. Nakamura, K. Takahashi, and M. Tsubota, J. Power Sources 64 (1–2) (1997) 147–152. [4] J. Valenciano, A. Sánchez, F. Trinidad, and A.F. Hollenkamp, J. Power Sources 158 (2) (2006) 851–863. [5] D. Pavlov, and P. Nikolov, J. Power Sources 242 (2013) 380–399.. [6] P.T. Moseley, D.A.J. Rand, and K. Peters, J. Power Sources 295 (2015) 268–274. [7] W. Zhang, H. Lin, H. Lu, D. Liu, J. Yin, and Z. Lin, J. Mater. Chem. A 3 (8) (2015) 4399–4404. [8] L. Wang, W. Zhang, L. Gu, Y. Gong, G. Cao, H. Zhao, Y. Yang, and H. Zhang, Electrochim. Acta 222 (2016), 376–384. [9] C. Zhao, W. Wang, Z. Yu, H. Zhang, A. Wang, and Y. Yang, J. Mater. Chem. 20 (2010) 976–980. [10] L.A. Yolshina, V.A. Yolshina, A.N. Yolshin, and S.V. Plaksin, J. Power Sources 278 (2015) 87–97.
8
Graphical abstract
Highlights
A hybrid additive consists of lead-doped porous carbon composite and graphite.
The additive with sheets attached to porous bulk inhibit irreversible sulfation.
The high-rate cycle life of lead-carbon battery is remarkably prolonged.
10