Influences of Ag doping on the high energy ball milling aided sintering FeSe superconductors

All‐Solid‐State Mg–Air Battery Enhanced with Free‐Standing N‐Doped 3D Nanoporous Graphene

“…Earth‐abundant element‐based metal–air batteries are crucial for realizing next‐generation high‐energy/power‐density energy storage technologies required for electric devices, sensors, and portable electronics in future carbon‐neutral societies. [ 1,2 ] Various metal–air batteries, such as Li, [ 3–7 ] Zn, [ 8–12 ] K, [ 13–15 ] Al, [ 16–19 ] Na, [ 20,21 ] Fe, [ 22 ] Si, [ 23 ] Ti, [ 24 ] and Mg, [ 25–29 ] have been developed. In terms of the battery performances, such as volumetric capacity and theoretical discharge voltage (Li: 5960 Wh L −1 /2.96 V, Zn: 9677 Wh L −1 /1.65 V, K: 1913 Wh L −1 /2.48 V, Al: 21 994 Wh L −1 /2.7 V, and Mg: 6859 Wh L −1 /3.09 V), [ 30–35 ] the Mg–air battery is highly effective.…”

Improving Superconducting Performance of Fe(Se, Te) with In Situ Formed Grain-Boundary Strengthening and Flux Pinning Centers

“…Despite their decent properties, there is still a long way to go for large-scale application of Fe­(Se, Te) superconductors due to the very low J c in Fe­(Se, Te) wires and tapes . Currently, the J c values of reported Fe­(Se, Te) wires or tapes fabricated by the traditional powder-in-tube process are only around 10 3 A/cm 2 , which are significantly lower than those of Fe­(Se, Te) single crystals or films (∼10 5 A/cm 2 ). − There are mainly two reasons for the low current capacity in Fe­(Se, Te) systems: (1) the intergrain weak links due to the existence of secondary phases and amorphous phases as well as pores − and (2) the presence of interstitial Fe, which can obviously degrade the intrinsic superconductivity of Fe­(Se, Te). , In the past decade, many methods have been proposed to improve the J c of Fe­(Se, Te) polycrystalline wires or tapes. − Based on previous reports, the incorporation of low-melting-point elements (Ag/Sn) has greatly strengthened the interaction at grain boundaries, thus improving the intergrain connections. − Moreover, the introduction of an oxygen postannealing treatment successfully eliminated the interstitial Fe in the single crystal system, and the superconducting properties were greatly improved with increased T c . − Due to the long diffusion distance in the bulk system, the oxygen annealing process cannot be adopted in Fe­(Se, Te) polycrystals . The development of a new technique for the reduction of interstitial Fe while maintaining or even enhancing the intergrain connections is necessary for the further development of Fe­(Se, Te)-based wires or tapes.…”