In this paper, we report the successful design and synthesis of a hierarchically porous MoS2/C composite aerogel by simple one-pot mass preparation. The synthesis involves the in situ formation of MoS2 nanosheets on agarose molecular chains, the gelation of MoS2-deposited agarose monomers to generate a composite hydrogel, and in situ transformation of the composite hydrogel into a MoS2/C composite aerogel through carbonization. This composite aerogel can be used as a high-performance electrode material for supercapacitors and lithium-ion batteries. When tested as a supercapacitor electrode, it achieves a high specific capacitance of 712.6 F g−1 at 1 A g−1 and 97.3% capacity retention after 13 000 cycles at 6 A g−1. In addition, as a lithium-ion battery electrode, it exhibits a superior rate capability (653.2 mA h g−1 at 0.1 A g−1 and 334.5 mA h g−1 at 5.0 A g−1) and an ultrahigh capacity retention of nearly 100% after 1000 cycles at 1 A g−1. These performances may be ascribed to the unique structure of the MoS2/C composite aerogel, such as hierarchical pores, (002) plane-expanded MoS2 and interconnected carbon networks embedded uniformly with MoS2 nanosheets. This work may provide a general and simple approach for mass preparation of composite aerogel materials and pave the way for promising materials applied in both supercapacitors and lithium-ion batteries.

The realization of antipulverization electrode structures, especially using low-carbon-content anode materials, is crucial for developing high-energy and long-life lithium-ion batteries (LIBs); however, this technology remains challenging. This study shows that SnO2 triple-shelled hollow superstructures (TSHSs) with a low carbon content (4.83%) constructed by layer-by-layer assembly of various nanostructure units can withstand a huge volume expansion of ≈231.8% and deliver a high reversible capacity of 1099 mAh g−1 even after 1450 cycles. These values represent the best comprehensive performance in SnO2-based anodes to date. Mechanics simulations and in situ transmission electron microscopy suggest that the TSHSs enable a self-synergistic structure-preservation behavior upon lithiation/delithiation, protecting the superstructures from collapse and guaranteeing the electrode structural integrity during long-term cycling. Specifically, the outer shells during lithiation processes are fully lithiated, preventing the overlithiation and the collapse of the inner shells; in turn, in delithiation processes, the underlithiated inner shells work as robust cores to support the huge volume contraction of the outer shells; meanwhile, the middle shells with abundant pores offer sufficient space to accommodate the volume change from the outer shell during both lithiation and delithiation. This study opens a new avenue in the development of high-performance LIBs for practical energy applications.

High-power sodium-ion batteries (SIBs) with long-term cycling attract increasing attention for large-scale energy storage. However, traditional SIBs toward practical applications still suffer from low rate capability and poor cycle induced by pulverization and amorphorization of anodes at high rate (over 5 C) during the fast ion insertion/extraction process. The present work demonstrates a robust strategy for a variety of (Sb–C, Bi–C, Sn–C, Ge–C, Sb–Bi–C) freestanding metal–carbon framework thin films via a space-confined superassembly (SCSA) strategy. The sodium-ion battery employing the Sb–C framework exhibits an unprecedented performance with a high specific capacity of 246 mAh g–1, long life cycle (5000 cycles), and superb capacity retention (almost 100%) at a high rate of 7.5 C (3.51A g–1). Further investigation indicates that the unique framework structure enables unusual reversible crystalline-phase transformation, guaranteeing the fast and long-cyclability sodium storage. This study may open an avenue to developing long-cycle-life and high-power SIBs for practical energy applications.

Semiconductor nanowires that have been extensively studied are typically in a crystalline phase. Much less studied are amorphous semiconductor nanowires due to the difficulty for their synthesis, despite a set of characteristics desirable for photoelectric devices, such as higher surface area, higher surface activity, and higher light harvesting. In this work of combined experiment and computation, taking Zn2GeO4 (ZGO) as an example, we propose a site-specific heteroatom substitution strategy through a solution-phase ions–alternative-deposition route to prepare amorphous/crystalline Si-incorporated ZGO nanowires with tunable band structures. The substitution of Si atoms for the Zn or Ge atoms distorts the bonding network to a different extent, leading to the formation of amorphous Zn1.7Si0.3GeO4 (ZSGO) or crystalline Zn2(GeO4)0.88(SiO4)0.12 (ZGSO) nanowires, respectively, with different bandgaps. The amorphous ZSGO nanowire arrays exhibit significantly enhanced performance in photoelectrochemical water splitting, such as higher and more stable photocurrent, and faster photoresponse and recovery, relative to crystalline ZGSO and ZGO nanowires in this work, as well as ZGO photocatalysts reported previously. The remarkable performance highlights the advantages of the ZSGO amorphous nanowires for photoelectric devices, such as higher light harvesting capability, faster charge separation, lower charge recombination, and higher surface catalytic activity.Keywords: amorphous nanowires; bonding distortion; photoelectrochemical water splitting; semiconductor; site-specific heteroatom substitution

The designed synthesis of mesocrystal materials and their advanced heterostructures in a simple, mild and low-cost way is of great significance, for the purpose of exploring their novel properties and large-scale applications. Herein, we report a unique one-pot additive-free route for the facile synthesis of novel strawberry-like Au nanostar/ZnO mesocrystal (Au NS/ZnO MC) heterostructures where Au nanostars were grown in the superficial layer of spherical ZnO mesocrystals. In situ synergistic crystallization of Au nanostars and ZnO mesocrystals accounts for the formation of Au NS/ZnO MC heterostructures with high-quality heterojunctions. The growth mechanism of the Au NS/ZnO MC heterostructures has been proposed on the basis of substantial evidence, which involves two sequential processes with morphology/structure evolution driven by surface energy minimization at two different dimensions. The novel Au NS/ZnO MC heterostructures that integrate Au nanostars and ZnO mesocrystals through high-quality Au–ZnO heterojunctions are expected to possess open architecture, high surface area, good electronic conductivity, and effective charge transfer interfaces, showing promise in a wide range of applications in solar cells, photocatalysis, gas sensors, etc. When employed as a sensing material towards H2S, the Au NS/ZnO MC electrode exhibits extraordinary performance including high sensitivity (≤5 ppb), high selectivity and low working temperature under stimulating realistic environmental conditions. The superior sensing performance can be ascribed to the synergistic effect that derives from the unique Au NS/ZnO MC heterostructures.

The designed synthesis of mesocrystal materials and their advanced heterostructures in a simple, mild and low-cost way is of great significance, for the purpose of exploring their novel properties and large-scale applications. Herein, we report a unique one-pot additive-free route for the facile synthesis of novel strawberry-like Au nanostar/ZnO mesocrystal (Au NS/ZnO MC) heterostructures where Au nanostars were grown in the superficial layer of spherical ZnO mesocrystals. In situ synergistic crystallization of Au nanostars and ZnO mesocrystals accounts for the formation of Au NS/ZnO MC heterostructures with high-quality heterojunctions. The growth mechanism of the Au NS/ZnO MC heterostructures has been proposed on the basis of substantial evidence, which involves two sequential processes with morphology/structure evolution driven by surface energy minimization at two different dimensions. The novel Au NS/ZnO MC heterostructures that integrate Au nanostars and ZnO mesocrystals through high-quality Au–ZnO heterojunctions are expected to possess open architecture, high surface area, good electronic conductivity, and effective charge transfer interfaces, showing promise in a wide range of applications in solar cells, photocatalysis, gas sensors, etc. When employed as a sensing material towards H2S, the Au NS/ZnO MC electrode exhibits extraordinary performance including high sensitivity (≤5 ppb), high selectivity and low working temperature under stimulating realistic environmental conditions. The superior sensing performance can be ascribed to the synergistic effect that derives from the unique Au NS/ZnO MC heterostructures.