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Hydrogen produced from neutral seawater electrolysis faces many challenges including high energy consumption, the corrosion/side reactions caused by Cl-, and the blockage of active sites by Ca2+/Mg2+ precipitates. Herein, we design a pH-asymmetric electrolyzer with a Na+ exchange membrane for direct seawater electrolysis, which can simultaneously prevent Cl- corrosion and Ca2+/Mg2+ precipitation and harvest the chemical potentials between the different electrolytes to reduce the required voltage. In-situ Raman spectroscopy and density functional theory calculations reveal that water dissociation can be promoted with a catalyst based on atomically dispersed Pt anchored to Ni-Fe-P nanowires with a reduced energy barrier (by 0.26 eV), thus accelerating the hydrogen evolution kinetics in seawater. Consequently, the asymmetric electrolyzer exhibits current densities of 10 mA cm−2 and 100 mA cm−2 at voltages of 1.31 V and 1.46 V, respectively. It can also reach 400 mA cm−2 at a low voltage of 1.66 V at 80 °C, corresponding to the electricity cost of US$1.36 per kg of H2 ($0.031/kW h for the electricity bill), lower than the United States Department of Energy 2025 target (US$1.4 per kg of H2). Hydrogen produced directly from neutral seawater is promising but challenging due to seawater's complex composition. Here, the authors report a Na+-conducted pH-asymmetric electrolyzer that can directly split seawater into hydrogen with low electricity cost and nearly zero chloride interference. [ABSTRACT FROM AUTHOR]

Antimony (Sb) based materials are regarded as promising anode materials for Li-ion batteries (LIBs) because of the high capacity, appropriate working potential, and earth abundance of antimony. However, the quick capacity decay due to the huge volume expansion during the cycling process seriously hinders its practical applications. Here, a nanocomposite of core@shell Sb@Sb 2 O 3 particles anchored on 3D porous nitrogen-doped carbon (3DNC) nanosheets is synthesized by freeze drying and sintering in a reducing atmosphere. Structural characterization shows that the developed Sb@Sb 2 O 3 /3DNC electrode has a high surface area (839.8 m 2 g -1 ) and unique Sb-O-C bonding, both contributing to the excellent electrochemical performance. The initial charge and discharge specific capacities of the Sb@ Sb 2 O 3 /3DNC anode in LIB tests are 1109 mA h g -1 and 1810 mA h g -1 , respectively. Also, it shows a charge capacity of 696.9 mA h g -1 after 500 cycles at 1 A g -1 and 458 mA h g -1 at a current density of 5 A g -1 . Moreover, the assembled Sb@Sb 2 O 3 /3DNC‖LiNi 0.6 Co 0.2 Mn 0.2 O 2 battery exhibits a discharge capacity of more than 100 mA h g -1 after 25 cycles at 100 mA g -1 . The synthetic method can be extended to obtain other nanocomposites of metal and carbon materials for high-performance energy storage devices., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)