Continuous electricity generation from solar heat and darkness

•Harvest solar heat in the daytime and darkness at night to make electricity•A charging-free TREC cell with record high efficiency power density•Dual-mode thermal regulation boosts thermal-to-electrical energy conversion As world marches into era of Internet Things (IoT), need for a pervasive solution sustainably billions distributed IoT devices exceeds capability traditional centralized supply systems. Photovoltaic cells have enabled generation during day but do not operate night. While thermoelectric generators were demonstrated enable battery-free off-grid lighting night, their outputs are restricted either limited spatial temperature difference or low Seebeck coefficient. Thus, efficient technologies sustainable all-day highly desired. In this work, we demonstrate low-cost continuous electricity generator convert diurnal variation via thermally regenerative electrochemical cycle (TREC) assistance dual-mode regulator, which could produce high-power both The electronics such as Internet-of-Things (IoT) sensors has stimulated extensive research on from environment electricity. However, it is challenging provide when photovoltaic systems no longer operate. graphene bifunctional absorber radiative cooler. This system lithium ferrocyanide iron phosphate can achieve 19.91% relative Carnot efficiency, almost five times highest reported TRECs. maximum density also ten best experimental rooftop demonstration shows its practical self-power greatly enhanced compared other Efficient harvesting desired free batteries cables.1Han C.G. Qian X. Li Q. Deng B. Zhu Y. Han Z. Zhang W. Wang Feng S.P. Chen G. 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Graphene, acting was integrated conversion. depicted Figure 1D, stands out state-of-the-art PV cells,38Best research-cell chart..https://www.nrel.gov/pv/cell-efficiency.htmlDate: 2023Google TEGs,2Raman TRECs.15Ding undergoes containing four consecutive steps: TH, TL, TL S1; S2 schematic open-circuit (OCV) T-ΔS plots ideal absolute isη=ΔT|α+−α−|qcμTH|α+−α−|qcμ+cp¯ΔT=ΔTTH+cp¯ΔT/(|α+−α−|qcμ)(Equation 1) where α+ α− couple, respectively. qc μ utilization couple cp¯ whole system. theoretical loss thermodynamic point view. η only dependent cp, qc, α, αand cp represent higher lead better evaluate systems, figure merit introduced asY=αqcμcp=μY′(Equation 2) Y′ electricity-assisted systems.8Lee It noted represents instinctive property itself. When paired TREC, Y actual considering part be utilized larger |Y| indicates half-cell i.e., |Y+−Y−|. widely used various thermogalvanic (TGC) coefficient,9Zhang Scholar,17Yu Scholar,39Duan Aqueous harvest.Nat. 5146https://doi.org/10.1038/s41467-018-07625-9Crossref enough, water strong K+ [Fe(CN)6]3−/4−. |Y|, Li+ much radius polarization molecules weaker replace boosted since greater stronger interaction partial charges molecule.20Li 2A compares K4 Li4 terms capacity, capacity. saturated over three K4, (2.31 M) S3). consumption S4). still S5). Therefore, unchanged reduced collectively endow considerably performance. pair Li3/Li4, LFP/FP, identical same cation excellent selected. 2B LFP comparisons PB KI3 K3/K4-based systems.15Ding good (Notes S4–S6). TRECs, active range 300–330 shown S13. 40%, 31% K3/K4-PB/PW 14% K3/K4-KI/KI3 Considering solubility, 0.92 M, 0.21 M 0.10 S7). 2C summarizes Yʹ showing stand them. S14 profiles Li3/Li4-LFP/FP cooperation great processes. use, results inevitable 1B, drop (i.e., IR I R resistance) leads decrease materials, resulting obvious work S2A. minimize loss, keeping 2 h eve