TY - JOUR AB - There is a need for the development of lead-free thermoelectric materials for medium-/high-temperature applications. Here, we report a thiol-free tin telluride (SnTe) precursor that can be thermally decomposed to produce SnTe crystals with sizes ranging from tens to several hundreds of nanometers. We further engineer SnTe–Cu2SnTe3 nanocomposites with a homogeneous phase distribution by decomposing the liquid SnTe precursor containing a dispersion of Cu1.5Te colloidal nanoparticles. The presence of Cu within the SnTe and the segregated semimetallic Cu2SnTe3 phase effectively improves the electrical conductivity of SnTe while simultaneously reducing the lattice thermal conductivity without compromising the Seebeck coefficient. Overall, power factors up to 3.63 mW m–1 K–2 and thermoelectric figures of merit up to 1.04 are obtained at 823 K, which represent a 167% enhancement compared with pristine SnTe. AU - Nan, Bingfei AU - Song, Xuan AU - Chang, Cheng AU - Xiao, Ke AU - Zhang, Yu AU - Yang, Linlin AU - Horta, Sharona AU - Li, Junshan AU - Lim, Khak Ho AU - Ibáñez, Maria AU - Cabot, Andreu ID - 13092 IS - 19 JF - ACS Applied Materials and Interfaces SN - 1944-8244 TI - Bottom-up synthesis of SnTe-based thermoelectric composites VL - 15 ER - TY - JOUR AB - Lithium–sulfur batteries are regarded as an advantageous option for meeting the growing demand for high-energy-density storage, but their commercialization relies on solving the current limitations of both sulfur cathodes and lithium metal anodes. In this scenario, the implementation of lithium sulfide (Li2S) cathodes compatible with alternative anode materials such as silicon has the potential to alleviate the safety concerns associated with lithium metal. In this direction, here, we report a sulfur cathode based on Li2S nanocrystals grown on a catalytic host consisting of CoFeP nanoparticles supported on tubular carbon nitride. Nanosized Li2S is incorporated into the host by a scalable liquid infiltration–evaporation method. Theoretical calculations and experimental results demonstrate that the CoFeP–CN composite can boost the polysulfide adsorption/conversion reaction kinetics and strongly reduce the initial overpotential activation barrier by stretching the Li–S bonds of Li2S. Besides, the ultrasmall size of the Li2S particles in the Li2S–CoFeP–CN composite cathode facilitates the initial activation. Overall, the Li2S–CoFeP–CN electrodes exhibit a low activation barrier of 2.56 V, a high initial capacity of 991 mA h gLi2S–1, and outstanding cyclability with a small fading rate of 0.029% per cycle over 800 cycles. Moreover, Si/Li2S full cells are assembled using the nanostructured Li2S–CoFeP–CN cathode and a prelithiated anode based on graphite-supported silicon nanowires. These Si/Li2S cells demonstrate high initial discharge capacities above 900 mA h gLi2S–1 and good cyclability with a capacity fading rate of 0.28% per cycle over 150 cycles. AU - Mollania, Hamid AU - Zhang, Chaoqi AU - Du, Ruifeng AU - Qi, Xueqiang AU - Li, Junshan AU - Horta, Sharona AU - Ibáñez, Maria AU - Keller, Caroline AU - Chenevier, Pascale AU - Oloomi-Buygi, Majid AU - Cabot, Andreu ID - 14719 IS - 50 JF - ACS Applied Materials and Interfaces SN - 1944-8244 TI - Nanostructured Li₂S cathodes for silicon-sulfur batteries VL - 15 ER - TY - JOUR AB - High-entropy materials offer numerous advantages as catalysts, including a flexible composition to tune the catalytic activity and selectivity and a large variety of adsorption/reaction sites for multistep or multiple reactions. Herein, we report on the synthesis, properties, and electrocatalytic performance of an amorphous high-entropy boride based on abundant transition metals, CoFeNiMnZnB. This metal boride provides excellent performance toward the oxygen evolution reaction (OER), including a low overpotential of 261 mV at 10 mA cm–2, a reduced Tafel slope of 56.8 mV dec–1, and very high stability. The outstanding OER performance of CoFeNiMnZnB is attributed to the synergistic interactions between the different metals, the leaching of Zn ions, the generation of oxygen vacancies, and the in situ formation of an amorphous oxyhydroxide at the CoFeNiMnZnB surface during the OER. AU - Wang, Xiang AU - Zuo, Yong AU - Horta, Sharona AU - He, Ren AU - Yang, Linlin AU - Ostovari Moghaddam, Ahmad AU - Ibáñez, Maria AU - Qi, Xueqiang AU - Cabot, Andreu ID - 12236 IS - 42 JF - ACS Applied Materials & Interfaces KW - General Materials Science SN - 1944-8244 TI - CoFeNiMnZnB as a high-entropy metal boride to boost the oxygen evolution reaction VL - 14 ER - TY - JOUR AB - Composite materials offer numerous advantages in a wide range of applications, including thermoelectrics. Here, semiconductor–metal composites are produced by just blending nanoparticles of a sulfide semiconductor obtained in aqueous solution and at room temperature with a metallic Cu powder. The obtained blend is annealed in a reducing atmosphere and afterward consolidated into dense polycrystalline pellets through spark plasma sintering (SPS). We observe that, during the annealing process, the presence of metallic copper activates a partial reduction of the PbS, resulting in the formation of PbS–Pb–CuxS composites. The presence of metallic lead during the SPS process habilitates the liquid-phase sintering of the composite. Besides, by comparing the transport properties of PbS, the PbS–Pb–CuxS composites, and PbS–CuxS composites obtained by blending PbS and CuxS nanoparticles, we demonstrate that the presence of metallic lead decisively contributes to a strong increase of the charge carrier concentration through spillover of charge carriers enabled by the low work function of lead. The increase in charge carrier concentration translates into much higher electrical conductivities and moderately lower Seebeck coefficients. These properties translate into power factors up to 2.1 mW m–1 K–2 at ambient temperature, well above those of PbS and PbS + CuxS. Additionally, the presence of multiple phases in the final composite results in a notable decrease in the lattice thermal conductivity. Overall, the introduction of metallic copper in the initial blend results in a significant improvement of the thermoelectric performance of PbS, reaching a dimensionless thermoelectric figure of merit ZT = 1.1 at 750 K, which represents about a 400% increase over bare PbS. Besides, an average ZTave = 0.72 in the temperature range 320–773 K is demonstrated. AU - Li, Mengyao AU - Liu, Yu AU - Zhang, Yu AU - Han, Xu AU - Xiao, Ke AU - Nabahat, Mehran AU - Arbiol, Jordi AU - Llorca, Jordi AU - Ibáñez, Maria AU - Cabot, Andreu ID - 10327 IS - 43 JF - ACS Applied Materials and Interfaces KW - CuxS KW - PbS KW - energy conversion KW - nanocomposite KW - nanoparticle KW - solution synthesis KW - thermoelectric SN - 1944-8244 TI - PbS–Pb–CuxS composites for thermoelectric application VL - 13 ER - TY - JOUR AB - We report a family of Pt and Pd benzoporphyrin dyes with versatile photophysical properties and easy access from cheap and abundant chemicals. Attaching 4 or 8 alkylsulfone groups onto a meso-tetraphenyltetrabenzoporphyrin (TPTBP) macrocylcle renders the dyes highly soluble in organic solvents, photostable, and electron-deficient with the redox potential raised up to 0.65 V versus the parent porphyrin. The new dyes intensively absorb in the blue (Soret band, 440–480 nm) and in the red (Q-band, 620–650 nm) parts of the electromagnetic spectrum and show bright phosphorescence at room-temperature in the NIR with quantum yields up to 30% in solution. The small singlet–triplet energy gap yields unusually efficient thermally activated delayed fluorescence (TADF) at elevated temperatures in solution and in polymeric matrices with quantum yields as high as 27% at 120 °C, which is remarkable for benzoporphyrins. Apart from oxygen sensing, these properties enable unprecedented simultaneous, self-referenced oxygen and temperature sensing with a single indicator dye: whereas oxygen can be determined either via the decay time of phosphorescence or TADF, the temperature is accessed via the ratio of the two emissions. Moreover, the dyes are efficient sensitizers for triplet–triplet annihilation (TTA)-based upconversion making possible longer sensitization wavelength than the conventional benzoporphyrin complexes. The Pt-octa-sulfone dye also features interesting semireversible transformation in basic media, which generates new NIR absorbing species. AU - Zach, Peter W. AU - Freunberger, Stefan Alexander AU - Klimant, Ingo AU - Borisov, Sergey M. ID - 7290 IS - 43 JF - ACS Applied Materials & Interfaces SN - 1944-8244 TI - Electron-deficient near-infrared Pt(II) and Pd(II) benzoporphyrins with dual phosphorescence and unusually efficient thermally activated delayed fluorescence: First demonstration of simultaneous oxygen and temperature sensing with a single emitter VL - 9 ER -