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Water electrolysis is considered the cleanest method for hydrogen production. However, the widespread popularization of water splitting is limited by the high cost and scarce resources of efficient platinum group metals. Hence, it is imperative to develop an economical and high‐performance electrocatalyst to improve the efficiency of hydrogen evolution reaction (HER). In this study, a hierarchical porous sandwich structure is fabricated through dealloying FeCoNiCuAl2Mn high‐entropy alloy (HEA). This free‐standing electrocatalyst shows outstanding HER performance with a very small overpotential of 9.7 mV at 10 mA cm−2 and a low Tafel slope of 56.9 mV dec−1 in 1 M KOH solution, outperforming commercial Pt/C. Furthermore, this electrocatalytic system recorded excellent reaction stability over 100 h with a constant current density of 100 mA cm−2. The enhanced electrochemical activity in high‐entropy alloys results from the cocktail effect, which is detected by density functional theory (DFT) calculation. Additionally, micron‐ and nano‐sized pores formed during etching boost mass transfer, ensuring sustained electrocatalyst performance even at high current densities. This work provides a new insight for development in the commercial electrocatalysts for water splitting. [ABSTRACT FROM AUTHOR]

The development prospects of conventional Li-ion batteries are limited by the paucity of Li resources. Mg–Li hybrid batteries (MLIBs) combine the advantages of Li-ion batteries and magnesium batteries. Li+ can migrate rapidly in the cathode materials, and the Mg anode has the advantage of being dendrite-free. In this study, a type of Li4Ti5O12 composite material doped with Sn4+ and a conductive carbon skeleton (Li4Ti4.9Sn0.1O12/C, Sn0.1-LTO/C) was prepared by a simple one-pot sol–gel method. The doped Sn4+ replaces part of Ti4+ in the crystal lattice, which makes Ti3+ require charge compensation, thus improving the ionic conductivity. The intervention of the conductive carbon skeleton further improves the conductivity of the Sn0.1-LTO/C composite material. The performance of Sn0.1-LTO/C as the cathode of MLIBs is explored. The initial discharge capacity was 159.1 mA h g−1 at 0.5 C, and it was maintained at 105 mA h g−1 even after 500 cycles. The excellent electrochemical performance is attributed to a small amount of Sn doping and the involvement of the conductive carbon skeleton, which indicated that the Sn0.1-LTO/C composite material provides great potential application in MLIBs. [ABSTRACT FROM AUTHOR]

In this work, the Sn-doped titanium niobate Snx-TiNb2O7 (Snx-TNO, x = 0.005, 0.01, 0.02, 004, 0.06, 0.08) samples have been fabricated through a solid-state reaction method with the aim of investigating the effect of Sn4+ doping on the electrochemical performance enhancement of TiNb2O7 (TNO). Elemental mapping image indicates that Sn is successfully doped and evenly distributed in the TNO sample. XRD patterns show that the doping of Sn4+ can slightly increase the lattice spacing of TNO materials, which can increase the diffusion coefficient of Li+ ions due to the ion-size effect. The specific capacity, capacity retention, long cycle performance, and rate performance of Snx-TNO materials are all superior to those of TNO, and Sn0.01-TNO has the best performance. Compared with TNO, Sn0.01-TNO exhibited a smaller polarization potential, indicating that the doping of tin elements resulted in a more efficient kinetic reaction process and a higher redox reversibility. The EIS results further verify that the Sn0.01-TNO material has a lower charge transfer impedance and a higher ion diffusion coefficient compared to the TNO material, resulting in better electrochemical performance of the Sn0.01-TNO material. The strategy of appropriate metal doping can improve the intrinsic electronic/ionic conductivity and structural stability of the material, providing new insights for the development of advanced high-power electrode materials. [ABSTRACT FROM AUTHOR]

The development prospects of conventional Li-ion batteries are limited by the paucity of Li resources. Mg-Li hybrid batteries (MLIBs) combine the advantages of Li-ion batteries and magnesium batteries. Li + can migrate rapidly in the cathode materials, and the Mg anode has the advantage of being dendrite-free. In this study, a type of Li 4 Ti 5 O 12 composite material doped with Sn 4+ and a conductive carbon skeleton (Li 4 Ti 4.9 Sn 0.1 O 12 /C, Sn 0.1 -LTO/C) was prepared by a simple one-pot sol-gel method. The doped Sn 4+ replaces part of Ti 4+ in the crystal lattice, which makes Ti 3+ require charge compensation, thus improving the ionic conductivity. The intervention of the conductive carbon skeleton further improves the conductivity of the Sn 0.1 -LTO/C composite material. The performance of Sn 0.1 -LTO/C as the cathode of MLIBs is explored. The initial discharge capacity was 159.1 mA h g -1 at 0.5 C, and it was maintained at 105 mA h g -1 even after 500 cycles. The excellent electrochemical performance is attributed to a small amount of Sn doping and the involvement of the conductive carbon skeleton, which indicated that the Sn 0.1 -LTO/C composite material provides great potential application in MLIBs.