Nanoporous silicon fiber networks in a composite anode for all-solid-state batteries with superior cycling performance.

All-solid-state batteries comprising Si anodes are promising materials for energy storage in electronic vehicles because their energy density is approximately 1.7 times higher than that of graphite anodes. However, Si undergoes severe volume changes during cycling, resulting in the loss of electronic and ionic conduction pathways and rapid capacity fading. To address this challenge, we developed composite anodes with a nanoporous Si fiber network structure in sulfide-based solid electrolytes (SEs) and conductive additives. Nanoporous Si fibers were fabricated by electrospinning, followed by magnesiothermic reduction. The total pore volume of the fibers allowed pore shrinkage to compensate for the volumetric expansion of Li12Si7, thereby suppressing outward expansion and preserving the Si-SE (or conductive additive) interface. The network structure of the lithiated Si fibers compensates for electronic and ionic conduction pathways even to the partially delaminated areas, leading to increased Si utilization. The anodes exhibited superior performance, achieving an initial Coulombic efficiency of 71%, a reversible capacity of 1474 mAh g-1, and capacity retention of 85% after 40 cycles with an industrially acceptable areal capacity of 1.3 mAh cm-2. The proposed approach can reduce the constraint pressure during charging/discharging and may have practical applications in large-area all-solid-state batteries.

Enhanced electric control of magnetic anisotropy via high thermal resistance capping layers in magnetic tunnel junctions.

We studied nonlinear magnetic anisotropy changes to the DC bias voltage of magnetic tunnel junctions (MTJs) with capping layers of different thermal resistances. We found that increasing the thickness of MgO capping layers (in the range 0.3-0.5 nm) in MTJs enhances the Joule heating-induced magnetic anisotropy change, which indicates an enhancement of the interfacial thermal resistance at the FeB|MgO capping layer interface. This enhanced interfacial thermal resistance may be attributed to roughness at the FeB|MgO interface. Moreover, we observed a larger power-driven magnetic anisotropy change of 3.21 µJ W-1m-1 in the MTJ with a composite MgO (0.3 nm)|W (2 nm)|MgO (0.4 nm) capping layer. This research supports methods of efficient spin manipulation of spintronic devices such as microwave devices and magnetic memories.

A novel symmetric TTF-pyridyl thiolato zinc complex: synthesis, characterization and crystal structure analysis.

We report the first preparation of a symmetric tetrathiafulvalene (TTF)-pyridyl thiolato zinc(ii) complex in which two TTF parts connect to the central zinc atom through pyridines and thiolates. We also discuss the crystal structure analysis and physical properties of the complex, especially photocurrent generations measured on its thin-film sample and single crystal.