Home Journals Articles Updates About
CN
image
收藏切换
Ultrafine RuO2 nanoparticles/MWCNTs cathodes for rechargeable Na-CO2 batteries with accelerated kinetics of Na2CO3 decomposition
收藏切换
PDF
Zhenzhen Wang, Yichao Cai, Youxuan Ni, Yong Lu, Liu Lin, Haoxiang Sun, Haixia Li, Zhenhua Yan, Qing Zhao*, Jun Chen
Chinese Chemical Letters | 2023, 34(3) : 107405
Less
收藏切换
Chinese Chemical Letters | 2023, 34(3): 107405
• Communication •
Ultrafine RuO2 nanoparticles/MWCNTs cathodes for rechargeable Na-CO2 batteries with accelerated kinetics of Na2CO3 decomposition
Full
Zhenzhen Wang, Yichao Cai, Youxuan Ni, Yong Lu, Liu Lin, Haoxiang Sun, Haixia Li, Zhenhua Yan, Qing Zhao*, Jun Chen
Affiliations
  • Haihe Laboratory of Sustainable Chemical Transformations, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin 300071, China
Published: 2023-03-15 doi: 10.1016/j.cclet.2022.04.003
Outline
收藏切换

Na-CO2 batteries have attracted extensive attention due to their high theoretical energy density (1125 Wh/kg), efficient utilization of CO2, and abundant sodium resources. However, they are trapped by the sluggish decomposition kinetic of discharge products (mainly Na2CO3) on cathode side during the charging process. Here we prepared a series of nano-composites composed of RuO2 nanoparticles in situ loaded on activated multi-walled carbon nanotubes (RuO2@a-MWCNTs) through hydrolyzing reaction followed by calcination method and used them as cathode catalysts to accelerate the decomposition of Na2CO3. Among all catalysts, the RuO2@a-MWCNTs with appropriate ratio of RuO2 (49.7 wt%) demonstrated best stability and rate performance in Na-CO2 batteries, benefiting from both high specific surface area (160.3 m2/g) and highly dispersed RuO2 with ultrafine nanostructures (~2 nm). At a limited capacity of 500 mAh/g, Na-CO2 batteries could afford the operation of over 120 cycles at 100 mA/g, and even at the current density to 500 mA/g, the charge voltage was still lower than 4.0 V after 40 cycles. Further theoretical calculations proved that RuO2 was the catalytically active center and contributed to the decomposition of Na2CO3 by weakening the C=O bond. The synergetic functions of high specific surface (CNTs) and high catalytic activity (RuO2) will inspire more progress on metal-CO2 batteries.

Na-CO2 batteries  /  Cathode catalyst  /  RuO2@a-MWCNTs  /  High rate performance  /  Low charge overpotential
Zhenzhen Wang, Yichao Cai, Youxuan Ni, Yong Lu, Liu Lin, Haoxiang Sun, Haixia Li, Zhenhua Yan, Qing Zhao, Jun Chen. Ultrafine RuO2 nanoparticles/MWCNTs cathodes for rechargeable Na-CO2 batteries with accelerated kinetics of Na2CO3 decomposition[J]. Chinese Chemical Letters, 2023 , 34 (3) : 107405 - . DOI: 10.1016/j.cclet.2022.04.003
Full Text
Less
Metal-CO2 batteries have recently attracted plenty of attention because they can utilize greenhouse gas CO2, along with their high specific energy density [1-4]. Moreover, it is promising to adopt metal-CO2 batteries as power supplies of future exploration on Mars, in which CO2 accounts for 95% of the atmosphere [5, 6]. Metal Li-CO2 batteries were firstly investigated and have been widely studied due to both high discharge potential (~2.8 V) and theoretical energy density (1876 Wh/kg) based on the ideal reaction of 4Li+3CO2↔2Li2CO3+C [7-9]. Plenty of catalysts such as RuO2, Ru, Mo2C, NiO have been developed to promote the decomposition of thermodynamically stable discharge products (Li2CO3) [10-16]. Considering the limited resource of lithium, sodium with similar physical and chemical properties has also been applied as anode to build Na-CO2 batteries, in which the theoretical energy density can reach 1125 Wh/kg through the reaction of 4Na+3CO2↔2Na2CO3+C (~2.35 V) [8, 17, 18].
Similar with Li-CO2 batteries, the discharge products of Na-CO2 batteries (Na2CO3) are also hard to decompose, leading to high charge overpotential and poor cycle stability [17-20]. In 2016, with electrolyte-treated multi-wall carbon nanotube (t-MWCNT) as cathode catalyst, we first enabled the rechargeable room temperature Na-CO2 battery [5]. Since then, a handful of catalysts such as Co2MnOx decorated carbon fiber, ZnCo2O4@CNT, ketjen black carbon or CNT supported ruthenium nanoparticles (Ru@KB or Ru@CNT), have been designed to accelerate the kinetics of the battery [7, 18, 21, 22]. Among them, nano-Ru metal composites stand out with high catalytic characteristics towards Na2CO3 decomposition, but their high reactivities undergo the concerns of catalyzing the decomposition of electrolyte [23, 24]. As an alternative, RuO2 catalyst, which is more stable than metal Ru, also exhibits decent electron conductivity. RuO2@CNTs have been applied as cathode catalysts in Li-CO2 batteries to facilitate the decomposition of Li2CO3 [25, 26], which triggers the interest to study the use of ruthenium oxide-based catalysts in Na-CO2 batteries.
Herein, a series of RuO2 nanoparticles in situ loaded on activated multi-walled carbon nanotubes (RuO2@a-MWCNTs) have been fabricated through the facile hydrolyzing reaction followed by calcination method [27-29] and acted as cathode catalysts to promote the decomposition of Na2CO3 in Na-CO2 batteries. Through optimizing the temperature of calcination and the content of RuO2, RuO2@a-MWCNTs prepared at 150 ℃ with 49.7 wt% RuO2 demonstrated the best overall performance. The charge/discharge overpotential has been reduced to 1.5 V, in contrast with pure a-MWCNTs catalyst (2.2 V). Further cycling test unveiled the charge voltage of Na-CO2 batteries with above catalyst were still lower than 4.0 V after 40 cycles at 500 mA/g and after 90 cycles at 100 mA/g under same limited capacity of 500 mAh/g. The results of density functional theory (DFT) calculations showed that RuO2 was the catalytically active site, and the Ru atoms on RuO2 and the O atoms on Na2CO3 formed covalent bonds, which resulted in the charge transfer on the C=O, elongated the length of C=O bond on the Na2CO3, and promoted the decomposition of Na2CO3 with low charging overpotential.
Various RuO2@a-MWCNTs composites were synthesized through the facile hydrolyzing reaction followed by calcination method. The detailed preparation process was shown in Fig. 1a. The precursor powder from the same batch was divided into three parts and calcined at 150 ℃, 180 ℃, and 200 ℃ for 10 h to obtain the final products, which were respectively defined as RuO2@a-MWCNTs-150 ℃, RuO2@a-MWCNTs-180 ℃, and RuO2@a-MWCNTs-200 ℃. The results from X-ray diffraction (XRD) indicated that the crystallization increased with the increasing of temperature (Fig. 1b). Pure a-MWCNTs displayed two diffraction peaks at 25.9° and 42.8° that could be assigned to the (002) and (100) planes [30], respectively. When the calcination temperature was 180 ℃ or higher, the obtained RuO2 in the composite exhibited decent crystallinity and the XRD patterns matched well with the standard card (PDF#88–323-RuO2) (Figs. S1 and S2 in Supporting information). For RuO2@a-MWCNTs-150 ℃, the crystallization of RuO2 was highly suppressed with only one broad diffraction peak centered at around 35°. Meanwhile, RuO2 nanoparticles were ultrafine and evenly dispersed on carbon nanotubes (Fig. 1c). However, RuO2 nanoparticles became larger and agglomerated together for RuO2@a-MWCNTs-180 ℃ (Fig. 1d) or 200 ℃ (Fig. 1e).
Considering that the catalysts with highly dispersed and ultra-fine characteristics can provide more active sites to accelerate the decomposition of Na2CO3 [31], we chose the calcination temperature of 150 ℃ to further optimize the loadings of RuO2 nanoparticles (Fig. S3 in Supporting information). The RuO2 content in the RuO2@a-MWCNTs composite was evaluated to be 56.8 wt% (labeled as RuO2@a-MWCNTs-1), 49.7 wt% (labeled as RuO2@a-MWCNTs-2), 27.9 wt% (labeled as RuO2@a-MWCNTs-3) according to the result of thermogravimetric (TG) analysis in air atmosphere (Fig. 2a and Fig. S4 in Supporting information). Based on the N2- adsorption-desorption measurement, the specific surface area of the composite gradually increased after decreasing the content of RuO2, which were 147.8, 160.3, 183.8 and 212.8 m2/g for RuO2@a-MWCNTs-1, RuO2@a-MWCNTs-2, RuO2@a-MWCNTs-3 and pristine a-MWCNTs, respectively (Fig. 2b). Nevertheless, the specific surface area for RuO2@a-MWCNTs composite was still high enough to accommodate the discharge product of Na-CO2 batteries with maintained porous structure [27].
We carried out the Transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM) and energy dispersive X-ray spectroscopy (EDX) to further investigate the distribution of RuO2 nanoparticles in a-MWCNTs (Figs. 2c-g and Figs. S5-S7 in Supporting information). High RuO2 content (RuO2@a-MWCNTs-1) would result in the aggregation of RuO2 nanoparticles (Fig. 2c and Fig. S5). Reducing the content of RuO2 nanoparticles (RuO2@a-MWCNTs-2) enable the uniform distribution of particles (Fig. 2d and Fig. S6). The RuO2 was more scattered when the content was further reduced (RuO2@a-MWCNTs-3) (Fig. 2e and Fig. S7). Through calibrating the lattice fringes and the angles between them, the HRTEM image (Fig. 2f) confirmed that the RuO2 of RuO2@a-MWCNTs-2 belonged to the cubic phase (PDF#87–726-RuO2) with average size of about 2 nm. EDX mapping of RuO2@a-MWCNTs-2 demonstrated Ru and O elements were uniformly distributed (Fig. 2g). X-ray photoelectron spectroscopy (XPS) was adopted to analyze the element valence and bonding states. The XPS high-resolution spectrum of Ru 3p (Fig. 2h) could be fitted to two peaks at 464.0 eV and 486.7 eV, indicating the dominant +4 oxidation state of Ru [31]. The O 1s XPS spectrum could be fitted to three peaks (Fig. 2i). The peak at binding energy of 532.8 eV and 531.4 eV corresponded to C-O and C=O [32, 33]. Compared with the XPS spectrum of a-MWCNTs (Fig. S8 in Supporting information), there was an additional peak with a binding energy of 530.2 eV in RuO2@a-MWCNTs-2, which was related to the Ru-O bond of RuO2 [34].
The above characterizations suggested that RuO2@a-MWCNTs-2 took advantages of both high dispersibility and abundant active sites. In order to further study the relationship between the loading ratio of RuO2 and the catalytic performance, we assembled Na-CO2 coin cells with RuO2@a-MWCNTs-1, RuO2@a-MWCNTs-2, RuO2@a-MWCNTs-3, or a-MWCNTs as cathode catalysts. The median charging voltage was a straightforward indicator to assess the catalytic capability for Na2CO3 decomposition (Figs. 3a-d and Figs. S9-S11 in Supporting information). Obviously, pure a-MWCNTs cathode exhibited the highest potential, exceeding 4 V even on the first lap. RuO2@a-MWCNTs-3 cathode with lowest content of RuO2 also demonstrated sharply increased overpotential that exceed 4 V on the 25th lap. Both RuO2@a-MWCNTs-1 and RuO2@a-MWCNTs-2 displayed low median charging voltage, while RuO2@a-MWCNTs-2 demonstrated higher durability and the charging potential was still lower than 4 V after 90 cycles. We attributed it to better dispersed RuO2 nanoparticles/higher specific surface area than RuO2@a-MWCNTs-1 and higher RuO2 ratio than RuO2@a-MWCNTs-3. Moreover, long cycle test at a limited capacity of 500 mAh/g demonstrated that Na-CO2 batteries could afford the operation of 70 cycles at 500 mA/g (Fig. 3e), in which the charge voltage was still lower than 4.0 V after 40 cycles at 500 mA/g. The charging voltage only increased by 0.2 V on the 20th lap when the current density increased from 100 mA/g to 500 mA/g (Fig. S12 in Supporting information). Fig. 3f and Fig. S13 (Supporting information) compared the performance of Na-CO2 battery between RuO2@a-MWCNTs-2 in this work and cathode catalysts reported in the literature (cut-off capacity was 500 mAh/g). Among all the cathode catalysts, RuO2@a-MWCNTs-2 catalyst displayed decent charge voltage at low current density (100 mA/g) on the first cycle, and the lowest charge voltage at high current density (500 mA/g) with longest cycling life.
In order to unveil how catalyst contributed to the reaction of Na-CO2 batteries, ex-situ XRD and scanning electron microscope (SEM) characterization have been conducted at different states of charge and discharge (6 state points were marked in Fig. 4a). Na-CO2 battery with RuO2@a-MWCNTs-2 catalyst exhibited outstanding reversibility. From the XRD graph (Fig. 4b), three diffraction peaks of Na2CO3 at 34.6°, 37.5° and 41.7° were emerged after discharge, and disappeared when charging process was finished. The reversibility was also confirmed by SEM characterization. Plenty of granular products were generated on the carbon nanotube skeleton during the discharge process (Figs. 4c-e and Fig. S14 in Supporting information). The products gradually disappeared, and a porous structure reappeared during the charging process (Figs. 4f-h and Fig. S15 in Supporting information). Even after 20 cycles with a cutoff capacity of 500 mAh/g at 100 mA/g, the RuO2@a-MWCNTs-2 cathode still showed intriguing catalytic properties for Na2CO3 decomposition, sharply contrasting with a-MWCNTs cathode on which a few by-products were accumulated (Fig. S16 in Supporting information). The intriguing results were due to the synergetic functions of CNTs and RuO2, in which multi-walled carbon nanotubes could provide a huge specific surface area to hold the discharge products, and the RuO2 nanoparticles could effectively reduce the energy barrier of electrochemical reaction during the charging process to promote the decomposition of Na2CO3. Moreover, the oxygen-containing functional groups carried by the activated carbon tubes (Figs. S17-S19 in Supporting information) enabled the uniform dispersion of RuO2 nanoparticles [6, 35, 36].
To provide atomic understanding between RuO2 based catalyst and Na2CO3, we further applied the density functional theory (DFT) calculations. Figs. 5a-c and Table S1 (in Supporting information) summarized the configurations of Na2CO3 on a-MWCNTs, RuO2 and RuO2@a-MWCNTs substrates. The results demonstrated that the adsorption energy of Na2CO3 on RuO2 (−3.578 eV) and RuO2@a-MWCNTs (−2.595 eV) were more negative than that on a-MWCNTs (−1.115 eV), indicating RuO2 was the preferred sites to grow Na2CO3. Besides, compared with the substrate of a-MWCNTs (1.289 Å, 1.288 Å), the C=O bond of Na2CO3 on the substrate of RuO2 (1.316 Å, 1.318 Å) and RuO2@a-MWCNTs (1.318 Å, 1.314 Å) were lengthened. The lengthened bond meant that Na2CO3 was easier to decompose, proving that RuO2 nanoparticles were beneficial for the charge process of Na-CO2 batteries.
The differential charge density was then used to explain that why the C=O bond length was elongated (Figs. 5d-f). Different from a-MWCNTs system, the electron density around the C=O bond of Na2CO3 decreased obviously in the RuO2 and RuO2@a-MWCNTs system, which was due to the covalent bond that formed between O atoms on the Na2CO3 and the Ru atoms on the RuO2. The newly formed Ru-O interaction directly weakened the C=O bond and thus favored the decomposition of Na2CO3. The DFT calculations unambiguously verified that the RuO2@a-MWCNTs composite cathode catalyst was very effective for fabricating the high stable Na-CO2 batteries.
In summary, ultra-fine and highly dispersed RuO2 nanoparticles (~2 nm) loaded on a-MWCNTs have been fabricated and for the first time, acted as cathode catalyst to reduce the charge overpotential and enhance the reversibility of Na-CO2 batteries. a-MWCNTs with O-rich groups facilitated the dispersion of RuO2 and RuO2 promoted Na2CO3 decomposition by weakening the C=O bond of Na2CO3, which together contributed to build the Na-CO2 batteries with long cycle life (> 120 cycles) and low charge potential (< 4.0 V up to 90 cycles). This work provides a general way to promote the decomposition of Na2CO3. With rational designation, more composite catalysts with advanced conductive host such as graphene, porous carbons, MXene can be prepared to further enhance the properties of metal-CO2 batteries.
Declaration of competing interest
Less
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
Less
This work was supported by the National Natural Science Foundation of China (Nos. 52001170, 21835004), the National Key R & D Program of China (Nos. 2017YFA0206700, 2021YFB2500300) and the Natural Science Foundation of Tianjin (No. 20JCQNJC02060).
Supplementary materials
Less
Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.cclet.2022.04.003.
References
Less
[1]
J. Sun, Y. Lu, H. Yang, et al., Research 2018 (2018) 6914626.
[2]
X. Mu, H. Pan, P. He, et al., Adv Mater. 32 (2019) e1903790.
[3]
Y. Hou, J. Wang, L. Liu, et al., Adv. Funct. Mater. 27 (2017) 1700564.
[4]
S. Shen, C. Han, B. Wang, et al., Chin. Chem. Lett. 33 (2022) 3721–3725.
[5]
X. Hu, J. Sun, Z. Li, et al., Angew. Chem. Int. Ed. 55 (2016) 6482–6486.
[6]
Y. Lu, Y. Cai, Q. Zhang, et al., Chem. Sci. 10 (2019) 4306–4312.
[7]
S. Thoka, C.M. Tsai, Z. Tong, et al., ACS Appl. Mater. Interfaces 13 (2021) 480–490.
[8]
S. Yang, Y. Qiao, P. He, et al., Energy Environ. Sci. 10 (2017) 972–978.
[9]
S. Ma, Y. Lu, H. Yao, et al., Chin. Chem. Lett. 33 (2022) 2933–2936.
[10]
Y. Dong, S. Li, S. Hong, L. Wang, B. Wang, Chin. Chem. Lett. 31 (2020) 635–642.
[11]
X. Zhang, C. Wang, H. Li, et al., J. Mater. Chem. A 6 (2018) 2792–2796.
[12]
Y. Xing, Y. Yang, D. Li, et al., Adv. Mater. 30 (2018) e1803124.
[13]
C. Yang, K. Guo, D. Yuan, et al., J. Am. Chem. Soc. 142 (2020) 6983–6990.
[14]
Z. Zhang, Q. Zhang, Y. Chen, et al., Angew. Chem. Int. Ed. 54 (2015) 6550–6553.
[15]
K. Chen, G. Huang, J.L. Ma, et al., Angew. Chem. Int. Ed. 59 (2020) 16661–16667.
[16]
R. Pipes, A. Bhargav, A. Manthiram, Adv. Energy Mater. 9 (2019) 1900453.
[17]
Z. Zheng, C. Wu, Q. Gu, et al., J. Energy Environ. Mater. 4 (2021) 158–177.
[18]
S. Thoka, Z. Tong, A. Jena, et al., J. Mater. Chem. A 8 (2020) 23974.
[19]
Z. Zhang, X.G. Wang, X. Zhang, et al., Adv. Sci. 5 (2018) 1700567.
[20]
L. Qie, Y. Lin, J.W. Connell, et al., Angew. Chem. Int. Ed. 56 (2017) 6970–6974.
[21]
L. Guo, B. Li, V. Thirumal, et al., Chem. Commun. 55 (2019) 7946–7949.
[22]
C. Fang, J. Luo, C. Jin, et al., ACS Appl. Mater. Interfaces 10 (2018) 17240–17248.
[23]
X. Xing, I. Kimihiko, K. Yoshimi, Electrochim. Acta 261 (2018) 323e329.
[24]
S. Ma, Y. Wu, J. Wang, et al., Nano Lett. 15 (2015) 8084–8090.
[25]
Z. Xie, X. Zhang, Z. Zhang, et al., Adv. Mater. 29 (2017) 1605891.
[26]
S. Bie, M. Du, W. He, et al., ACS Appl. Mater. Interfaces 11 (2019) 5146–5151.
[27]
Y. Eda, Y. Chihiro, Y. Keisuke, et al., Nano Lett. 13 (2013) 4679–4684.
[28]
P. Xua, C. Chen, J. Zhu, et al., J. Electroanal. Chem. 842 (2019) 98–106.
[29]
Z. Jian, P. Liu, F. Li, et al., Angew. Chem. Int. Ed. 53 (2014) 442–446.
[30]
R. Wang, X. Zhang, Y. Cai, et al., Nano Res. 12 (2019) 2543–2548.
[31]
S. -. M. Xu, Z. -. C. Ren, X. Liu, et al., Energy Storage Mater. 15 (2018) 291–298.
[32]
M. Chuai, J. Yang, M. Wang, et al., eScience 1 (2021) 178–185.
[33]
S. Kundu, Y. Wang, W. Xia, et al., J. Phys. Chem. C 112 (2008) 16869–16878.
[34]
X. Gao, J. Chen, X. Sun, et al., ACS Appl. Nano Mater. 3 (2020) 12269–12277.
[35]
A. Huang, Y. Ma, J. Peng, et al., eScience 1 (2021) 141–162.
[36]
J.G. Zhou, H.T. Fang, Y.F. Hu, et al., J. Phys. Chem. C 113 (2009) 10747–10750.
Appendix
Less
Year 2023 volume 34 Issue 3
PDF
43
26
Cite this Article
BibTeX
Article Info
doi: 10.1016/j.cclet.2022.04.003
  • Receive Date：2022-03-05
  • Online Date：2025-11-21
  • Published：2023-03-15
Article Data
Affiliations
History
  • Received：2022-03-05
  • Revised：2022-03-26
  • Accepted：2022-04-02
Affiliations
    Haihe Laboratory of Sustainable Chemical Transformations, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin 300071, China
References
Share
https://castjournals.cast.org.cn/joweb/ccl/EN/10.1016/j.cclet.2022.04.003
Share to
QR

Scan QR to access full text

Cite this article
BibTeX
Citations
表12种不同金属材料的力学参数
科
Family		 属数
Number of
genus		 种数
Number of
species		 占总种数比例
Percentage of
total species (%)		 属
Genus		 种数
Number of
species		 占总种数比例
Percentage of total
species (%)
鹅膏菌科Amanitaceae 2 11 5.26 鹅膏菌属 Amanita 10 4.78
小菇科 Mycenaceae 2 12 5.74 丝盖伞属 Inocybe 5 2.39
多孔菌科 Polyporaceae 8 14 6.70 蜡蘑属 Laccaria 5 2.39
红菇科 Russulaceae 3 23 11.00 小皮伞属 Marasmius 6 2.87
小菇属 Mycena 11 5.26
光柄菇属 Pluteus 5 2.39
红菇属 Russula 17 8.13
栓菌属 Trametes 5 2.39
关闭全屏
  • BibTeX
  • EndNote
  • RefWorks
  • TxT
Links
Articles
Latest Articles
Most Read
Collections
Updates
Events
News
Multimedia
About
About Us
Contact
No. 86 Xueyuan South Road, Haidian District, Beijing
100081
010-62199257
qkjq@cast.org.cn

Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House