Crystal Facet and Architecture Engineering of Metal Oxide Nanonetwork Anodes for High-Performance Potassium Ion Batteries and Hybrid Capacitors.

Metal oxides are considered as prospective dual-functional anode candidates for potassium ion batteries (PIBs) and hybrid capacitors (PIHCs) because of their abundance and high theoretic gravimetric capacity; however, due to the inherent insulating property of wide band gaps and deficient ion-transport kinetics, metal oxide anodes exhibit poor K+ electrochemical performance. In this work, we report crystal facet and architecture engineering of metal oxides to achieve significantly enhanced K+ storage performance. A bismuth antimonate (BiSbO4) nanonetwork with an architecture of perpendicularly crossed single crystal nanorods of majorly exposed (001) planes are synthesized via CTAB-mediated growth. (001) is found to be the preferential surface diffusion path for superior adsorption and K+ transport, and in addition, the interconnected nanorods gives rise to a robust matrix to enhance electrical conductivity and ion transport, as well as buffering dramatic volume change during insertion/extraction of K+. Thanks to the synergistic effect of facet and structural engineering of BiSbO4 electrodes, a stable dual conversion-alloying mechanism based on reversible six-electron transfer per formula unit of ternary metal oxides is realized, proceeding by reversible coexistence of potassium peroxide conversion reactions (KO2↔K2O) and BixSby alloying reactions (BiSb ↔ KBiSb ↔ K3BiSb). As a result, BiSbO4 nanonetwork anodes show outstanding potassium ion storage in terms of capacity, cycling life, and rate capability. Finally, the implementation of a BiSbO4 nanonetwork anode in the state-of-the-art full cell configuration of both PIBs and PIHCs shows satisfactory performance in a Ragone plot that sheds light on their practical applications for a wide range of K+-based energy storage devices. We believe this study will propose a promising avenue to design advanced hierarchical nanostructures of ternary or binary conversion-type materials for PIBs, PIHCs, or even for extensive energy storage.

Synthesis of raspberry-like antimony-platinum (SbPt) nanoparticles as highly active electrocatalysts for hydrogen evolution reaction.

Binary transition metals can facilitate the hydrogen evolution reaction (HER) through the synergistic integration of different electrochemical properties. To determine binary transition metals that are highly active, Greely et al. conducted a simulation of 256 different binary transition metals. They demonstrated that BiPt, PtRu, AsPt, SbPt, BiRh, RhRe, PtRe, AsRu, IrRu, RhRu, IrRe, and PtRh could be used as efficient electrocatalysts for HER. However, only few of them are synthesized and used as electrocatalysts. In this work, we report the synthesis of the raspberry-like antimony-platinum (SbPt) nanoparticles (NPs) via a colloidal nanocrystal synthesis. These NPs exhibited efficient activity with a low overpotential of 27 mV to reach 10 mA cm-2 in acidic media. We conducted long-term durability test for 90,000 s under an applied voltage of 0.5 V (vs. RHE) and cycling tests of over 10,000 cycles under an applied voltage of 0.1 to -0.5 V (vs. RHE). The high activity exhibited by the raspberry-like SbPt NPs may be due to the following reasons: (1) the raspberry-like SbPt NPs exhibited versatile active exposed (110), (100), (101), and (012) facets as efficient HER catalysts, and (2) as confirmed by both the density functional theory (DFT) simulation and experimental results, the presence of Sb 3d subsurface broadened the Pt surface d-band, which caused synergistic effects on water splitting. In summary, synthesis of the new colloidal raspberry-like SbPt NPs is essential to elucidate the fundamental properties of the nanomaterial and nanostructure design. This study could facilitate the development of Pt-group materials that can be used as HER catalysts.

Correction: Colloidal synthesis of porous red phosphorus nanoparticles as a metal-free electrocatalyst for the hydrogen evolution reaction.

Correction for 'Colloidal synthesis of porous red phosphorus nanoparticles as a metal-free electrocatalyst for the hydrogen evolution reaction' by Cheng-Ying Chan et al., Chem. Commun., 2020, 56, 2937-2940, DOI: .

Colloidal synthesis of porous red phosphorus nanoparticles as a metal-free electrocatalyst for the hydrogen evolution reaction.

Porous red phosphorus nanoparticles, P-RPNPs, were synthesized via a new colloidal approach and used as metal-free electrocatalysts in the hydrogen evolution reaction (HER). P-RPNPs were highly efficient in acidic media, required an overpotential of only 218 mV to reach 10 mA cm-2, and exhibited superior long-term durability.

Substrate properties modulate cell membrane roughness by way of actin filaments.

Cell membrane roughness has been proposed as a sensitive feature to reflect cellular physiological conditions. In order to know whether membrane roughness is associated with the substrate properties, we employed the non-interferometric wide-field optical profilometry (NIWOP) technique to measure the membrane roughness of living mouse embryonic fibroblasts with different conditions of the culture substrate. By controlling the surface density of fibronectin (FN) coated on the substrate, we found that cells exhibited higher membrane roughness as the FN density increased in company with larger focal adhesion (FA) sizes. The examination of membrane roughness was also confirmed with atomic force microscopy. Using reagents altering actin or microtubule cytoskeletons, we provided evidence that the dynamics of actin filaments rather than that of microtubules plays a crucial role for the regulation of membrane roughness. By changing the substrate rigidity, we further demonstrated that the cells seeded on compliant gels exhibited significantly lower membrane roughness and smaller FAs than the cells on rigid substrate. Taken together, our data suggest that the magnitude of membrane roughness is modulated by way of actin dynamics in cells responding to substrate properties.