Luminescent nanothermometers have shown competitive superiority for contactless and noninvasive temperature probing especially at the nanoscale. Herein, we report the inherently Eu /Eu codoped Sc O nanoparticles synthesized via a one-step and controllable thermolysis reaction where Eu is in-situ reduced to Eu by oleylamine. The stable luminescence emission of Eu as internal standard and the sensitive response of Eu emission to temperature as probe comprise a perfect ratiometric nanothermometer with wide-range temperature probing (77-267 K), high repeatability (>99.94%), and high relative sensitivity (3.06% K at 267 K). The in situ reduction of Eu to Eu ensures both uniform distribution in the crystal lattice and simultaneous response upon light excitation of Eu /Eu . To widen this concept, Tb is codoped as additional internal reference for tunable temperature probing range.

The structural and dynamical changes in the solvation shell surrounding Li+ in a multianion environment are studied by Raman spectroscopy and molecular dynamics (MD) simulations. The ternary electrolyte is composed of a mixture of two ionic liquids (ILs), n-methyl-n-propylpyrrolidinium bis­(trifluoromethanesulfonyl)­imide ([PYR13]­[TFSI]) and 1-ethyl-3-methylimidazolium dicyanamide ([EMIM]­[DCA]), and a lithium bis­(trifluoromethanesulfonyl)­imide ([Li]­[TFSI]) salt (0–1 M). A 1:9 volumetric mixture of [PYR13]­[TFSI]/[EMIM]­[DCA] formed an eutectic that exhibited a lower melting point than that of either parent IL. The local structure of Li+ in this eutectic is found to be heterogenous and preferentially solvated by [DCA], which is the smaller and more abundant anion. Whereas [TFSI] is able to bridge multiple Li+ at high salt concentrations and form both monodentate and bidentate conformations through its oxygen atoms, [DCA] is capable of forming only monodentate coordination with Li+ through either of its end nitrogen atoms. The Raman and MD analyses suggest a wide distribution of solvation structures in the form of [Li­(TFSI) m (DCA) n ](m+n−1)– where m = 0–1 and n = 3–4. The computations showed increased ion pair lifetime for Li+–[DCA] and decreased lifetimes for Li+–[TFSI] in the ternary mixture with the increase in the [Li]­[TFSI] concentration. These results show that the solvation and transport properties of charge carriers in ILs can be modified via the presence of multiple ions with varying degree of coordination, which provides an approach to impact the performance in electrochemical processes.

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Ion accessibility, large surface area, and complete wetting of a carbonaceous electrode by the electrolyte are crucial for high-performance electrochemical double-layer capacitors. Herein, we report a facile and scalable method to prepare electrode-electrolyte hybrid materials, where an ionic liquid (IL) electrolyte is encapsulated within a shell of reduced graphene oxide (rGO) nanosheets as the active electrode material (called rGO-IL capsules). These structures were templated using a Pickering emulsion consisting of a dispersed phase of 1-methyl-3-butylimidazolium hexafluorophosphate ([bmim][PF]) and a continuous water phase; graphene oxide nanosheets were used as the surfactant, and interfacial polymerization yielded polyurea that bound the nanosheets together to form the capsule shell. This method prevents the aggregation and restacking of GO nanosheets and allows wetting of the materials by IL. The chemical composition, thermal properties, morphology, and electrochemical behavior of these new hybrid architectures are fully characterized. Specific capacitances of 80 F g at 18 °C and 127 F g at 60 °C were achieved at a scan rate of 10 mV s for symmetric coin cells of rGO-IL capsules. These architected materials have higher capacitance at low temperature (18 °C) across many scan rates (10-500 mV s) compared with analogous cells with the porous carbon YP-50. These results demonstrate a distinct and important methodology to enhance the performance of electrochemical double-layer capacitors by incorporating electrolyte and carbon material together during synthesis.