Thermoelectric Enhancements in PbTe Alloys Due to Dislocation-Induced Strains and Converged Bands.

In-grain dislocation-induced lattice strain fluctuations are recently revealed as an effective avenue for minimizing the lattice thermal conductivity. This effect could be integratable with electronic enhancements such as by band convergence, for a great advancement in thermoelectric performance. This motivates the current work to focus on the thermoelectric enhancements of p-type PbTe alloys, where monotelluride-alloying and Na-doping are used for a simultaneous manipulation on both dislocation and band structures.

Novel All-Nitrogen Molecular Crystals of Aromatic N.

Nitrogen has unique bonding ability to form single, double, and triple bonds, similar to that of carbon. However, a molecular crystal formed by an aromatic polynitrogen similar to a carbon system has not been found yet. Herein, a new form of stable all-nitrogen molecular crystals consisting of only bispentazole N molecules with exceedingly high energy density is predicted.

Pressure-Induced Structural Evolution and Bandgap Optimization of Lead-Free Halide Double Perovskite (NH)SeBr.

Lead-free halide double perovskites (HDPs) are promising candidates for high-performance solar cells because of their environmentally-friendly property and chemical stability in air. The power conversion efficiency of HDPs-based solar cells needs to be further improved before their commercialization in the market. It requires a thoughtful understanding of the correlation between their specific structure and property.

Moving to Aqueous Binder: A Valid Approach to Achieving High-Rate Capability and Long-Term Durability for Sodium-Ion Battery.

Polyanionic NaV(PO)F with a NASICON-type structure is heralded as a promising cathode material for sodium-ion batteries due to its fast ionic conduction, high working voltage, and favorable structural stability. However, a number of challenging issues remain regarding its rate capability and cycle life, which must be addressed to enable greater application compatibility. Here, a facile and effective approach that can be used to overcome these disadvantages by introducing an aqueous carboxymethyl cellulose (CMC) binder is reported.

Formation and Diffusion of Metal Impurities in Perovskite Solar Cell Material CHNHPbI: Implications on Solar Cell Degradation and Choice of Electrode.

Solar cells based on methylammonium lead triiodide (MAPbI) have shown remarkable progress in recent years and have demonstrated efficiencies greater than 20%. However, the long-term stability of MAPbI-based solar cells has yet to be achieved. Besides the well-known chemical and thermal instabilities, significant native ion migration in lead halide perovskites leads to current-voltage hysteresis and photoinduced phase segregation.

Towards High-Safe Lithium Metal Anodes: Suppressing Lithium Dendrites via Tuning Surface Energy.

The formation of lithium dendrites induces the notorious safety issue and poor cycling life of energy storage devices, such as lithium-sulfur and lithium-air batteries. We propose a surface energy model to describe the complex interface between the lithium anode and electrolyte. A universal strategy of hindering formation of lithium dendrites via tuning surface energy of the relevant thin film growth is suggested.