9 research outputs found
Synthesis of ErFeAsO-based superconductors by hydrogen doping method
Here we demonstrate the technique to stabilize the ErFeAsO-based
superconductor with the smallest lattice constants in LnFeAsO1-y (Ln =
lanthanide) series using hydrogen doping method. Polycrystalline samples were
synthesized by heating pellets with nominal compositions of ErFeAsO1-y (1-y =
0.75 ~ 0.95) sandwiched between pellets of LaFeAsO0.8H0.8 compositions at 1100
{\deg}C under a pressure of 5.0 - 5.5 GP. The sample with lattice constants of
a = 3.8219 {\AA} and c = 8.2807 {\AA} shows the highest superconducting
critical temperatures (Tc) of 44.5 K and 41.0 K determined by onset transitions
of resistivity and susceptibility, respectively. We discuss phase diagram of Ln
dependence of Tc in LnFeAsO-based superconductors.Comment: 12 Pages, 5 Figures, Accepted for publication in EP
Interpretation of Abnormal AC Loss Peak Based on Vortex-Molecule Model for a Multicomponent Cuprate Superconductor
Growth and Characterization of CdTe Single Crystals Prepared by the “Liquinert Processed” Vertical Bridgman Method for Radiation Detectors
Observation of the Gap Distribution on Multi-layered Cuprate Superconductor Ba2Ca4Cu5O10(O1-x, Fx)2 by STM/STS
Black Phosphorus as a High-Capacity, High-Capability Negative Electrode for Sodium-Ion Batteries: Investigation of the Electrode/Electrolyte Interface
For a nonaqueous sodium-ion battery
(NIB), phosphorus materials
have been studied as the highest-capacity negative electrodes. However,
the large volume change of phosphorus upon cycling at low voltage
causes the formation of new active surfaces and potentially results
in electrolyte decomposition at the active surface, which remains
one of the major limiting factors for the long cycling life of batteries.
In this present study, powerful surface characterization techniques
are combined for investigation on the electrode/electrolyte interface
of the black phosphorus electrodes with polyacrylate binder to understand
the formation of a solid electrolyte interphase (SEI) in alkyl carbonate
ester and its evolution during cycling. The hard X-ray photoelectron
spectroscopy (HAXPES) analysis suggests that SEI (passive film) consists
of mainly inorganic species, which originate from decomposition of
electrolyte solvents and additives. The thicker surface layer is formed
during cycling in the additive-free electrolyte, compared to that
in the electrolyte with fluoroethylene carbonate (FEC) or vinylene
carbonate (VC) additive. The HAXPES and time-of-flight secondary ion
mass spectroscopy (TOF-SIMS) studies further reveal accumulation of
organic carbonate species near the surface and inorganic salt decomposition
species. These findings open paths for further improvement for the
cyclability of phosphorus electrodes for high-energy NIBs