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Chen Q, Gao L, Liu T, Marchetti A, Chen J, Pan H, Kong X. Structural Evolution of Lithium-Exchanged Na 3(VO) 2(PO 4) 2F Cathode under Operation in Sodium Ion Batteries. J Phys Chem Lett 2024; 15:1062-1069. [PMID: 38259053 DOI: 10.1021/acs.jpclett.3c03191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Na superionic conductor (NASICON)-type Na3(VO)2(PO4)2F (NVOPF) exhibits excellent cycling stability for high-voltage sodium ion batteries. Various strategies have been developed to form ion-exchanged NVOPF which can enhance the ionic and electronic conductivity. However, the underlying ion transport mechanism and complex structural transitions during battery operation remained uninvestigated. In this work, we prepared lithium-exchanged NVOPF (namely NLVOPF) which shows improved ionic conductivity and increased capacity at high discharging rates. Solid-state nuclear magnetic resonance (SSNMR) revealed the distinctive presence of two kinds of Li-exchanged sites in the NLVOPF, which are attributed to the occupied lithium ions at the Na1 and Na2 sites (namely Li1 and Li2, respectively). The Li1 site was metastably replaced in the first cycle, yet the Li2 site participated in ion insertion/extraction in the subsequent cycles. Our characterizations show that the dynamic doping of lithium in NLVOPF could contribute to the improved cycling stability and capacity retention.
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Affiliation(s)
- Qinlong Chen
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China
| | - Lina Gao
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China
- Zhejiang Huayou Cobal Company Limited, Tongxiang 314500, P. R. China
| | - Tingyu Liu
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China
| | | | - Juner Chen
- School of Engineering, Westlake University, Hangzhou 310030, P. R. China
| | - Huilin Pan
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China
| | - Xueqian Kong
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China
- Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
- Department of Physical Medicine and Rehabilitation, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310027, P. R. China
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Zhang W, Xue W, Xiao K, Visvanathan C, Tang J, Li L. Selection and optimization of carbon-based electrode materials for flow-electrode capacitive deionization. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2023.123649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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Luo L, He Q, Yi D, Zu D, Ma J, Chen Y. Indirect charging of carbon by aqueous redox mediators contributes to the enhanced desalination performance in flow-electrode CDI. WATER RESEARCH 2022; 220:118688. [PMID: 35661514 DOI: 10.1016/j.watres.2022.118688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/24/2022] [Accepted: 05/28/2022] [Indexed: 06/15/2023]
Abstract
Reversible electrochemical separation based on flow electrodes (e.g., flow-electrode capacitive deionization (FCDI)) is promising to desalinate brackish water, a reliable alternative source of freshwater. The deployment of redox mediators (RMs) in FCDI offers an energy-efficient means to improve the process performance, but the nature of the RMs-mediated charge transfer remains poorly understand. We therefore systematically investigated commonly-used RMs including sodium anthraquinone-2-sulfonate (AQS), 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO), hydroquinone (HQ) and ferricyanide ([Fe(CN)6]3-). Results showed that the desalination rate could be increased by over 260% with the addition of 10 mM [Fe(CN)6]3-. The lowest efficiency of AQS among the RMs should be ascribed to its reduction potential of -0.84 V (vs. Ag/AgCl) exceeding the potential (-0.48 V) of the negatively charged current collector at 1.2 V. While aqueous TEMPO and HQ could facilitate salt removal, their loss of efficiencies upon sorption onto the carbon surface indicated the insignificant pseudocapacitive contribution to ion migration. In-situ cyclic voltammetry measurements demonstrated the crucial role of the indirect charging of the flowable carbon materials to enhance the desalination performance in RMs-mediated FCDI. To sum up, results of this work pave a way to understand the RMs-mediated charge transfer and ion migration in FCDI, which would serve the purpose of design and optimization of the flow electrode systems for wider environmental applications.
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Affiliation(s)
- Liang Luo
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400044, China
| | - Qiang He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400044, China
| | - Duo Yi
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400044, China
| | - Daoyuan Zu
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Jinxing Ma
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China.
| | - Yi Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400044, China.
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High efficient and continuous recovery of iodine in saline wastewater by flow-electrode capacitive deionization. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.121419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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