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Dong H, Liu C, Huang Q, Chen Y. Se-induced defective carbon nanotubes promoting superior kinetics and electrochemical performance in Na 3V 2(PO 4) 3 for half and full Na ion cells. J Colloid Interface Sci 2024; 660:277-289. [PMID: 38244495 DOI: 10.1016/j.jcis.2024.01.087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/02/2024] [Accepted: 01/12/2024] [Indexed: 01/22/2024]
Abstract
Na3V2(PO4)3 (NVP), with unique Na super ionic conductivity (NASICON) framework, has become an prospective cathode material. However, the low electronic conductivity and poor structural stability limit its further development. Currently, the optimized carbon nanotubes (CNTs) by selenium doping are utilized to modify NVP system for the first time. Notably, the introduction of selenium in CNTs promotes to generate more defects, resulting in abundant active sites for the de-intercalation of Na+ to achieve more pseudocapacitance. Moreover, the newly formative C-Se bonds possess much stronger bond energy than the original CC (586.6 KJ mol-1 vs 377.4 KJ mol-1) bonds. The structure arrangement of the original CNTs is significantly improved by the doped selenium element, indicating that an enhanced carbon skeleton could be obtained to sustain the structural stability of NVP system. Furthermore, the excess selenium can be doped into the bulk of NVP crystal to replace of partial oxygen. Due to the larger ionic of Se2- (1.98 Å vs 1.4 Å of O2-), the VSe6 group has larger framework, which provides a broadened pathway for Na+ migration to improve the kinetic characteristics. Accordingly, the modified NVP@CNTs:Se = 1:1 sample exhibits superior rate capability and cyclic performance. It reveals high capacities of 78.6 and 76.5 mAh/g at 20 and 60C, maintaining 65.4 and 53.8 mAh/g after 5000 and 7000 cycles with high capacity retention of 84.49 % and 70.32 %, respectively. The assembled NVP@CNTs:Se = 1:1//CHC full cell delivers a high value of 153.6 mAh/g, suggesting the optimized sample also behaves excellent application potentials.
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Affiliation(s)
- Haodi Dong
- School of Environment and Safety Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China
| | - Changcheng Liu
- School of Environment and Safety Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China.
| | - Que Huang
- School of Environment and Safety Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; School of Resources and Safety Engineering, Central South University, Changsha 410010, Hunan, People's Republic of China.
| | - Yanjun Chen
- Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; School of Materials Science and Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China.
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Dong H, Liu C, Huang Q, Chen Y. Enhanced performance of Sn-doped Na 3V 2(PO 4) 3 with CNT integration for high-efficiency sodium-ion batteries. J Colloid Interface Sci 2024; 660:356-369. [PMID: 38244502 DOI: 10.1016/j.jcis.2024.01.088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/01/2024] [Accepted: 01/12/2024] [Indexed: 01/22/2024]
Abstract
The development of Na3V2(PO4)3 (NVP) has been severely hindered by low conductivity and unstable crystal structure. A simultaneously optimized strategy of Na-rich and Sn substitution is proposed for the first time. SnX-NVP@CNTs with different doping gradients are successfully prepared by the facile sol-gel method. Notably, more hole carriers can be generated by introducing Sn2+, thus improving its electron transport efficiency. In addition, since Sn2+ ions have a larger ion radius; when replacing V3+ ions at pillar positions, the lattice spacing can be enlarged to improve the structural stability of electrode materials. Meanwhile, it is beneficial to the movement of deep-level Na+ ions and improves the utilization rate of electrode materials. Moreover, to achieve charge compensation, it is necessary to introduce excess Na+ to the Sn-doped NVP system, which will increase the number of Na+ involved in the deintercalation process and improve its reversible capacity. Furthermore, the dense coating of CNTs can form an efficient conductive network structure, which improves the electron transport rate and inhibits the accumulation of active grains to accelerate Na+ diffusion. Under the synergistic adjustment of Sn2+ doping and CNTs enwrapping, the prepared Sn0.07-NVP@CNTs exhibit a high reversible capacity of 115.1 mAh/g at 0.1C, and the capacity retention rate reaches 89.35 % after 2000 cycles at 10C. Even after 10,000 cycles at 60C, its reversible capacity dropped from the initial 75.9 to 51.3 mAh/g, with a capacity loss of only 0.003 % per cycle. Besides, the Sn0.07-NVP@CNTs//CHC full battery releases a capacity of 139.9 mAh/g, highlighting its great potential for actual applications.
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Affiliation(s)
- Haodi Dong
- School of Environment and Safety Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China
| | - Changcheng Liu
- School of Environment and Safety Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China.
| | - Que Huang
- School of Environment and Safety Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; School of Resources and Safety Engineering, Central South University, Changsha 410010, Hunan, People's Republic of China.
| | - Yanjun Chen
- Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; School of Materials Science and Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China.
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Huang Q, Qian C, Liu C, Chen Y. Simultaneous modification of dual-substitution with CeO 2 coating boosting high performance sodium ion batteries. J Colloid Interface Sci 2024; 654:626-638. [PMID: 37864868 DOI: 10.1016/j.jcis.2023.10.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 10/13/2023] [Accepted: 10/16/2023] [Indexed: 10/23/2023]
Abstract
Na3V2(PO4)3 (NVP) is highly valued based on the stable construction among the polyanionic compounds. Nevertheless, the drawback of low intrinsic conductivity has been impeded its further application. In this paper, the internal channels of the crystal structure are extended by the introduction of larger radius Ce3+, which increases the transport rate of Na+. The introduction of Mo6+ replacing the V site leads to a beneficial n-type doping effect and facilitates the transportation of electrons. Besides, CeO2 cladding is introduced to further enhance the electronic conductivity of NVP system. Initially, CeO2 serves as an n-type semiconductor and functions as a conductive additive to significantly enhance the electronic conductivity of the electrode, thereby improving the electrochemical characteristics. Moreover, CeO2 functions as an oxygen buffer, aiding in the maintenance of active metal dispersion during operation and enabling efficient electron transfer between CeO2 and [VO6] octahedra in NVP, thus fostering outstanding electrical connectivity between the oxides. CeO2 cladding can be effectively integrated with the carbon layer to stabilize the NVP system. Comprehensively, the modified Na3V1.79Ce0.07Mo0.07(PO4)3/C@8wt.%CeO2 (CeMo0.07@8wt.%CeO2) composite exhibits excellent rate and cycling properties. It delivers a capacity of 113.4 mAh/g at 1C with a capacity retention rate of 80.3 % after 150 cycles. Even at 10C and 40C, it also submits high capacities of 84.7 mAh/g and 76 mAh/g, respectively. Furthermore, the CHC//CeMo0.07@8wt.%CeO2 asymmetric full cell possesses excellent sodium storage property, indicating its prospective application potentials.
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Affiliation(s)
- Que Huang
- School of Environment and Safety Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; School of Resources and Safety Engineering, Central South University, Changsha 410010, Hunan, People's Republic of China
| | - Chenghao Qian
- School of Environment and Safety Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China.
| | - Changcheng Liu
- School of Environment and Safety Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China.
| | - Yanjun Chen
- Institute of Advanced Energy Materials and Systems, North University of China, Taiyuan 030051, Shanxi, People's Republic of China; School of Materials Science and Engineering, North University of China, Taiyuan 030051, Shanxi, People's Republic of China.
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Yue L, Wang J, Li M, Qin J, Cao M. Conductive Ti 3C 2T x networks to optimize Na 3V 2O 2(PO 4) 2F cathodes for improved rate capability and low-temperature operation. Dalton Trans 2023; 52:4717-4727. [PMID: 36939215 DOI: 10.1039/d3dt00124e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Na3V2O2(PO4)2F (NVOPF) is gaining attention as a high-energy cathode candidate for sodium-ion batteries owing to its wide operating voltage, high energy density and excellent thermal stability. However, its intrinsic poor electrical conductivity results in its current sodium-storage performance being far below expectations. Herein, two-dimensional Ti3C2Tx MXene nanosheets with excellent electrical conductivity are introduced to construct an interconnected conductive framework to tightly encapsulate NVOPF nanoparticles. The Ti3C2Tx nanosheets ensure superior electronic contacts, along with inhibiting the agglomeration of NVOPF nanoparticles, thus accelerating electron and ion transfer during sodium-ion de/intercalation and maximizing the storage capacity. As a result, the optimized NVOPF/Ti3C2Tx cathode exhibits high rate capabilities (111 mA h g-1 at 0.2 C and 78 mA h g-1 at 20 C), with an impressively high capacity retention of 74.8% over a wide temperature range (from -20 to 20 °C). Additionally, the assembled sodium-ion full cell provides a highly reversible capacity of 116 mA h g-1 at 1 C, with a capacity retention of 67.2% after 100 cycles. These inspiring results provide new insights for improving the charge-transfer kinetics of the NVOPF cathode and this methodology may be extended to other cathode materials.
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Affiliation(s)
- Lufeng Yue
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China.
| | - Jie Wang
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China.
| | - Minxi Li
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China.
| | - Jinwen Qin
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China.
| | - Minhua Cao
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China.
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