Spontaneous spin selectivity and linear magnetoelectric effect in chiral molecules

Chirality-induced spin selectivity (CISS) has been extensively studied over the past two decades. While current-induced spin polarization in chiral molecules is widely recognized as the fundamental principle of the CISS, only a few studies have been reported on bias-current-free CISS, where there is no bias electric current in chiral molecules. In this paper, we discuss the microscopic origin of bias-free CISS using chiral molecule/ferromagnet bilayer systems. Recent studies on the chirality-induced exchange bias and current-in-plane magnetoresistance (CIP-MR) effects indicate that chiral molecules possess thermally driven broken-time-reversal symmetry at the interface, which induces bias-current-free CISS, i.e. a spontaneous effective magnetic field in the system. We also discuss the possibility of the linear magnetoelectric effect of chiral molecules at the interface and its potential impact on the observed CISS phenomena

Rate Performance of LiCoO2 Half-cells Using Highly Concentrated Lithium Bis(fluorosulfonyl)amide Electrolytes and Their Relevance to Transport Properties

For the rapid charge-discharge performance of Li-ion batteries (LIBs), ionic conductivity (σ) and Li ion transference number (t+) are important parameters of electrolytes. Electrolytes with high t+ alleviate the concentration polarization upon fast charge-discharge, and prevent the diffusion-limited mass transfer of Li+ ions. Recent studies have suggested that certain highly concentrated electrolytes exhibit better rate performances than conventional organic electrolytes despite their lower σ. However, the relationship between the transport properties (t+ and σ) of highly concentrated electrolytes and the enhanced rate performance of LIBs is yet to be elucidated. To evaluate the rate performance of LIBs with highly concentrated electrolytes in terms of transport properties, we investigated the discharge rate capability of LiCoO2 (LCO) half-cells using highly concentrated lithium bis(fluorosulfonyl)amide (Li[FSA]) electrolyte in γ-butyrolactone (GBL), acetonitrile (AN), dimethyl carbonate (DMC), and 1,2-dimethoxyethane (DME) solvents. There was a remarkable solvent dependence of t+, and the highest tLi+current of 0.67 was observed for GBL-based electrolyte measured using the very-low-frequency impedance spectroscopy (VLF–IS) method. The LCO half-cell with GBL-based electrolyte delivered higher discharge capacities than the cells with DMC- and DME-based electrolytes at high current densities. The improved rate performance in GBL-based electrolytes was attributable to enhanced Li+ ion mass transfer derived from the high tLi+current. We demonstrated the importance of tLi+current on the rate capability of LCO half-cells with highly concentrated electrolytes for high-rate battery performance