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X-ray scattering measurements were utilized to probe the effects of pressure on a series of ionic liquids, N-alkyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr1A-TFSI) (A = 3, 6, and 9), along with mixtures of ionic liquid and 30 mol.% lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. No evidence was found for crystallization of the pure ionic liquids or salt mixtures even at pressures up to 9.2 GPa. No phase separation or demixing was observed for the ionic liquid and salt mixtures. Shifts in the peak positions are indicative of compression of the ionic liquids and mixtures up to 2 GPa, after which samples reach a region of relative incompressibility, possibly indicative of a transition to a glassy state. With the application of pressure, the intensity of the prepeak was found to decrease significantly, indicating a reduction in cation alkyl chain aggregation. Additionally, incompressibility of the scattering peak associated with the distance between like-charges in the pure ionic liquids compared to that in mixtures with lithium salt suggests that the application of pressure could inhibit Li+ coordination with TFSI to form Li[TFSI2] complexes. This inhibition occurs through the suppression of TFSI in the trans conformer, in favor of the smaller cis conformer, at high pressures. [ABSTRACT FROM AUTHOR]

Here we report on the complex nature of the phase diagram of N-alkyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide ionic liquids using several complementary techniques and on their structural order in the molten state using small-wide angle x-ray scattering. The latter study indicates that the piperidinium aliphatic alkyl chains tend to aggregate, forming alkyl domains embedded into polar regions, similar to what we recently highlighted in the case of other ionic liquids. [ABSTRACT FROM AUTHOR]

Herein, we report a hard carbon derived from industrial bio-waste, i.e., pectin-free apple pomace. The structural, morphological, and electrochemical properties of the hard carbon are reported. The impact of the bio-waste on the closed porosity is discussed, providing valuable insights into the sodium storage mechanism in hard carbons. Most importantly, the hard carbon delivers good electrochemical performance, high specific capacities of 285 mAh g−1, and a very good capacity retention of 96% after 230 cycles at 0.1 C. [ABSTRACT FROM AUTHOR]