Lower-cost thermoelectrics: Thermoelectric materials convert heat to electricity, making them attractive for heat harvesting or cooling applications. However, many high-performance thermoelectrics are made of expensive or toxic materials. He et al. found that a material composed of primarily tin and sulfur could be optimized to have relatively good thermoelectric properties. Introducing about 10% selenium to tin sulfide helped tune these properties by electronic band manipulation. This material is a step toward more earth-abundant, less toxic, and lower-cost thermoelectrics than the telluride-based materials currently in use. Science , this issue p. 1418

Fe₂O₃ nanorods exposing (001) and (010) plane as well as Fe₂O₃ nanosheets exposing (001) plane have been successfully synthesized. Fe₂O₃ nanosheets exhibit better cycle performance and rate capabilities than that of Fe₂O₃ nanorods. The discharge capacity of Fe₂O₃ nanosheets can stabilize at 865 mAh/g at the rate of 0.2 C (1C = 1000 mA/g) and 570 mAh/g at the rate of 1.2 C after 80 cycles, which increased by 90% and 79% compared with 456 mAh/g and 318 mAh/g of Fe₂O₃ nanorods. In comparison with (010) plane, the (001) plane of hematite possesses larger packing density of Fe³⁺ and O²⁻, which is responsible for the superior electrochemical performances of Fe₂O₃ nanosheets than that of Fe₂O₃ nanorods. In addition, potentiostatic intermittent titration (PITT) results show the diffusion coefficients of Li⁺ (D_Li) of Fe₂O₃ nanosheets is higher than that of Fe₂O₃ nanorods. The higher diffusion coefficients of Li⁺ is favorable for the excellent lithium-storage capabilities and rate capability of Fe₂O₃ nanosheets. Inspired by our results, we can design and synthesize Fe₂O₃ or other electrodes with high performances according to their structure features in future.

A highly ordered interface between LiFePO₄ phase and FePO₄ phase with staging structure along the a axis and perpendicular to the b axis direction has been observed for the first time, in a partially chemically delithiated Li_0.90Nb_0.02FePO₄ by advanced aberration-corrected annular-bright-field (ABF) scanning transmission electron microscopy (STEM).