{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T16:06:30Z","timestamp":1790697990596,"version":"4.1.0"},"reference-count":19,"publisher":"American Chemical Society (ACS)","issue":"38","license":[{"start":{"date-parts":[[2026,9,6]],"date-time":"2026-09-06T00:00:00Z","timestamp":1788652800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100005118","name":"Japan Atomic Energy Agency","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100005118","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001691","name":"Japan Society for the Promotion of Science","doi-asserted-by":"publisher","award":["22K19001"],"award-info":[{"award-number":["22K19001"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,9,29]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Thermoelectric materials capable of operating at 600\u2013900 \u00b0C are attractive for recovering industrial and nuclear waste heat toward a carbon-neutral society. Here, we report the structure-guided enhancement of high-temperature thermoelectric performance in natural weathered biotite (WB) through molten-salt treatment using a KCl\u2013CaCl2 mixed salt (molar ratio 3:1) combined with systematic process optimization. The effects of WB particle size (&amp;lt;45 and 45\u201375 \u03bcm), salt addition ratio (1\/100\u20131\/1 by mass relative to WB), and compaction pressure (150\u2013200 MPa) on crystal structure, densification behavior, and thermoelectric transport properties were systematically examined. Structural and compositional analyses revealed progressive incorporation of K and Ca with increasing salt addition while largely preserving the layered WB framework, together with additional diffraction features indicating reaction-induced structural modifications. Among the conditions investigated, samples prepared from WB with an intermediate particle size of 45\u201375 \u03bcm exhibited relatively high packing densities (&amp;gt;70%) at low salt addition levels and showed enhanced electrical conductivity, whereas excessive particle refinement (&amp;lt;45 \u03bcm) suppressed electrical transport, indicating that the transport response is sensitive to particle-size-dependent packing and processing-induced microstructural variation. High-temperature measurements further revealed exceptionally large Seebeck coefficients of up to \u223c1.9 \u00d7 105 \u03bcV K\u20131, indicating that nonelectronic contributions may be involved in the observed thermovoltage. At present, the origin of this anomalously large response has not been conclusively established and requires further dedicated investigation. As a result of the cooperative optimization of particle size, salt addition, and compaction pressure, a maximum thermoelectric figure of merit of ZT = 0.29 at 667 \u00b0C was achieved, representing a marked improvement in this material system. These results demonstrate that microstructural control and densification strongly influence the measured thermoelectric response in layered silicate minerals and provide useful process\u2013structure\u2013property insights for natural mineral-derived high-temperature thermoelectric materials.<\/jats:p>","DOI":"10.1021\/acsomega.6c05333","type":"journal-article","created":{"date-parts":[[2026,9,6]],"date-time":"2026-09-06T16:01:22Z","timestamp":1788710482000},"page":"57250-57258","source":"Crossref","is-referenced-by-count":0,"title":["Structure-Guided\nEnhancement of High-Temperature Thermoelectric\nPerformance in Molten-Salt-Derived Weathered Biotite for Waste-Heat\nRecovery"],"prefix":"10.1021","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1485-0642","authenticated-orcid":true,"given":"Mitsunori","family":"Honda","sequence":"first","affiliation":[{"name":"Japan Atomic Energy Agency (JAEA) , , 2-4, Shirakata, Tokai-mura , Naka-gun, ,","place":["Ibaraki, Japan, 319-1195"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kosetsu","family":"Hayakawa","sequence":"additional","affiliation":[{"name":"Japan Atomic Energy Agency (JAEA) , , 2-4, Shirakata, Tokai-mura , Naka-gun, ,","place":["Ibaraki, Japan, 319-1195"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yumeno","family":"Masebo","sequence":"additional","affiliation":[{"name":"University of Tsukuba , , 1-1-1 Tennodai , , ,","place":["Tsukuba, Ibaraki, Japan, 305-8573"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masakazu","family":"Muraguchi","sequence":"additional","affiliation":[{"name":"Hokkaido University of Science , , 7-Jo 15-4-1 Maeda , Teine-ku, , ,","place":["Sapporo, Hokkaido, Japan, 006-8585"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rina","family":"Yabuta","sequence":"additional","affiliation":[{"name":"Japan Atomic Energy Agency (JAEA) , , 2-4, Shirakata, Tokai-mura , Naka-gun, ,","place":["Ibaraki, Japan, 319-1195"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masato","family":"Oda","sequence":"additional","affiliation":[{"name":"Wakayama University , , Sakaedani930 , , ,","place":["Wakayama-city, Wakayama, Japan, 640-8510"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hiroyuki","family":"Ishii","sequence":"additional","affiliation":[{"name":"University of Tsukuba , , 1-1-1 Tennodai , , ,","place":["Tsukuba, Ibaraki, Japan, 305-8573"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,9,6]]},"reference":[{"issue":"February","key":"2026092911090086600_cit1","doi-asserted-by":"publisher","first-page":"207","DOI":"10.1016\/j.applthermaleng.2018.04.043","article-title":"Industrial Waste Heat: Estimation of the Technically\nAvailable Resource in the EU per Industrial Sector, Temperature Level\nand Country","volume":"138","author":"Papapetrou","year":"2018","journal-title":"Appl. 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Prog.\nPhys."},{"key":"2026092911090086600_cit5","volume-title":"CRC Handbook of Thermoelectrics","author":"Rowe","year":"1995"},{"issue":"2","key":"2026092911090086600_cit6","doi-asserted-by":"publisher","first-page":"721","DOI":"10.1021\/acsomega.6b00372","article-title":"Mechanism of Cs Removal\nfrom Fukushima Weathered Biotite by Heat\nTreatment with a NaCl\u2013CaCl 2 Mixed Salt","volume":"2","author":"Honda","year":"2017","journal-title":"ACS Omega"},{"issue":"12","key":"2026092911090086600_cit7","doi-asserted-by":"publisher","first-page":"8678","DOI":"10.1021\/acsomega.7b01304","article-title":"Proposed Cesium-Free\nMineralization Method for Soil Decontamination:\nDemonstration of Cesium Removal from Weathered Biotite","volume":"2","author":"Honda","year":"2017","journal-title":"ACS Omega"},{"key":"2026092911090086600_cit8","doi-asserted-by":"publisher","first-page":"055034","DOI":"10.1063\/5.0206317","article-title":"Sustainable Thermoelectric\nMaterials: Utilizing Fukushima Weathered Biotite via Molten Salt Treatment","volume":"14","author":"Honda","year":"2024","journal-title":"AIP Adv."},{"key":"2026092911090086600_cit9","doi-asserted-by":"publisher","first-page":"0","DOI":"10.1063\/1.5038675","article-title":"Composites\nwith NiSb Nanocoating","volume":"125304","author":"Nandihalli","year":"2018","journal-title":"AIP Adv."},{"key":"2026092911090086600_cit10","doi-asserted-by":"publisher","first-page":"5428","DOI":"10.1039\/D1RA06133J","article-title":"Review on Grain\nSize e Ff Ects on Thermal Conductivity in ZnO Thermoelectric Materials","volume":"12","author":"Sulaiman","year":"2022","journal-title":"RSC Adv."},{"key":"2026092911090086600_cit11","doi-asserted-by":"publisher","first-page":"394","DOI":"10.1007\/s12274-009-9039-2","article-title":"Thermoelectric Properties\nof P-Type PbSe Nanowires","volume":"2","author":"Liang","year":"2009","journal-title":"Nano Res."},{"issue":"5","key":"2026092911090086600_cit12","doi-asserted-by":"publisher","first-page":"3954","DOI":"10.1021\/nn200474d","article-title":"Observation\nof Anisotropy in Thermal Conductivity of Individual Single- Crystalline\nBismuth Nanowires","volume":"5","author":"Roh","year":"2011","journal-title":"ACS Nano"},{"key":"2026092911090086600_cit13","doi-asserted-by":"publisher","first-page":"318","DOI":"10.3390\/ma17020318","article-title":"Effect of\nStarting Powder Particle Size on the Thermoelectric Properties of\nHot-Pressed Bi0.3Sb1.7Te3 Alloys","volume":"17","author":"Ioannou","year":"2024","journal-title":"Materials"},{"key":"2026092911090086600_cit14","doi-asserted-by":"publisher","first-page":"13760","DOI":"10.1038\/s41598-017-14013-8","article-title":"The Role of Grain Boundary Scattering in Reducing\nthe Thermal Conductivity of Polycrystalline X NiSn (X = Hf, Zr, Ti)\nHalf-Heusler Alloys","volume":"7","author":"Schrade","year":"2017","journal-title":"Sci. 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Phys."},{"key":"2026092911090086600_cit18","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1038\/s41467-019-08930-7","article-title":"Polymer Gels\nwith Tunable Ionic Seebeck\nCoefficient for Ultra-Sensitive Printed Thermopiles","volume":"10","author":"Zhao","year":"2019","journal-title":"Nat. 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