The experimentation carried out during this part of study allowed the synthesis and characterization of solid electrolytes for all-solid-state batteries. Aliovalent substitution of phosphorus for silicon enhanced ion conductivity significantly. Similarly, isovalent substitution with antimony showed improved ionic conductivity, but stability issues arose during the charge and discharge cycling. Computational investigations identified challenges and suggested future refinements for potential improvements.<\/p>\n","protected":false},"author":93,"featured_media":0,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"tags":[1302,1301],"targets":[],"rapporti_tipologie":[762],"class_list":["post-204495","rapporti","type-rapporti","status-publish","hentry","tag-batteries","tag-sodium-ion-batteries","rapporti_tipologie-report-en"],"acf":{"dont_show_hompage":true,"projects":{"ID":188409,"post_author":"93","post_date":"2024-06-13 15:10:21","post_date_gmt":"2024-06-13 13:10:21","post_content":"","post_title":"Electrochemical and thermal storage technologies","post_excerpt":"The goal of this project is to develop electrochemical and thermal storage technologies with improved performance and greater environmental and economic sustainability by optimizing the use of resources, material formulations and synthesis methods, diagnostic and control processes, and prototype design.","post_status":"publish","comment_status":"open","ping_status":"closed","post_password":"","post_name":"electrochemical-and-thermal-storage-technologies","to_ping":"","pinged":"","post_modified":"2024-07-06 15:23:41","post_modified_gmt":"2024-07-06 13:23:41","post_content_filtered":"","post_parent":0,"guid":"https:\/\/www.rse-web.it\/progetti\/electrochemical-and-thermal-storage-technologies\/","menu_order":0,"post_type":"progetti","post_mime_type":"","comment_count":"0","filter":"raw"},"order_posts":"","dont_show_search":false,"related_posts":false,"show_on_slider":false,"single_post_data":{"titolo_spot":"","post_content":"
The first part of this study has been focused on the synthesis and characterization of solid electrolytes in the Na(4-x)Si(1-x)P(x)S4 family for use in all-solid-state batteries. Aliovalent substitution of phosphorus (P) for silicon (Si) is investigated to modify the lattice polarizability, diffusion pathways and charge carrier concentration, so enhancing ion conductivity. The synthesized materials are characterized by various techniques, including X-ray diffraction, Raman spectroscopy and electrochemical impedance spectroscopy.<\/p>\n
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P successfully substitute with Si in Na4SiS4, leading to the formation of Na(4-x)Si(1-x)P(x)S4 phases. The study confirms that P can occupy same tetrahedral symmetry positions of Si and improves the ionic conductivity of the material. By substituting 16% of P with Si, the ionic conductivity is increased by 25 times compared to the pristine Na4SiS4. In addition, activation energy related to conduction has also been investigated, finding that higher P content in the solid electrolyte leads to lower activation energy, increasing the mobility of sodium ions through the material. Furthermore, a galvanostatic charge and discharge test is conducted using the solid electrolyte in an all-solid-state battery configuration, showing promising results for possible applications.<\/p>\n
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Overall, the study demonstrates the potential of aliovalent substitution in enhancing the properties of solid electrolytes for all-solid-state batteries, opening possibilities for the development of more efficient and cost-effective battery technologies, as well as safer ones.<\/p>\n
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The second study has been focused on the synthesis and characterization of solid electrolytes in the Na3P(1-x)Sb(x)S4 family. Isovalent substitution is employed to enhance ion conductivity by introducing larger isovalent atoms, such as Sb, in place of P, without generating Na vacancies. The crystal structure of Na3P(1-x)Sb(x)S4 materials has been better investigated using Rietveld analysis, revealing a volume expansion with increasing Sb content, which facilitates sodium ion conductivity. Bond Valence Pathway analysis shows 3D conduction pathways, indicating improved ionic conductivity with higher Sb content. Ionic conductivity measurements confirm increased conductivity and decreased activation energy as Sb content rises.<\/p>\n
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Galvanostatic charge-discharge tests in a full-cell configuration show initial promise, but the solid electrolyte with 100% Sb was unstable towards the anode. The electrolytes with 75% Sb (Sb75) showed better performance, but they undergo degradation during cycling, which reduces their capacity.Further work aims to address the stability issue and explore alternative anode materials to achieve improved battery performance.<\/p>\n
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The last part of the study focuses on initial computational investigations of Na3PS4 and Na3SbS4 solid electrolyte families. The aim was to identify the capabilities, and possible limitations, of computational analysis of Na ion conduction and finding the best solutions. First, classical physics methods have been used to obtain transferable interatomic potentials. The diffusion coefficients and conductivity of Na3PS4 and Na3SbS4 have been determined using these potentials. Preliminary Buckingham potentials for Na3PS4 and Na3SbS4 showed promise but lacked accuracy at higher temperatures. To address this, density functional theory (DFT) calculations have been used for improved potential fitting.<\/p>\n
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To improve the calculations this study the use of larger supercells is encouraged in overcoming challenges due to overestimation of vacancy sites. Finally, future objectives have been identified for further refining the interatomic potentials, investigating Nudged Elastic Band (NEB) simulations and using larger dopants such as W and Mo.<\/p>\n
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The Report is available on the Italian site<\/strong><\/p>\n","link_estreno":false,"scarica_file":false,"button":{"text":"","link":""},"referente_group":false,"data_emissione":"2023-06-30","autori":"M. Radaelli, M. Soleimanzade (RSE S.p.A.), M. Ravalli (Universit\u00e0 di Pavia)","rapporto":"","rif_rse":"23007503"},"satellite_post_url":""},"yoast_head":"\n