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[Display omitted] • Ni nano-clusters are anchored on TiN porous nanowires. • Ni nano-clusters balance active site exposure and reaction kinetics. • Ni nano-clusters anchored on TiN provide a highly active surface for OER. • Theoretical calculation confirms the experimental results and mechanism. Metal cluster catalysts have aroused much interest in the field of electrocatalysis due to high degree of materials utilization and strong substrate interaction, but negative effects such as materials aggregation must be minimized. In this work, rhizobia-like Ni nano-clusters encapsulated with a carbon network are anchored on porous TiN nanowire arrays prepared on carbon cloth (CC) to form a high-performance electrocatalyst for the oxygen evolution reaction (OER) in water splitting. The Ni nano-clusters with a small size and strong interaction with the TiN substrate provide active sites galore to facilitate OER. Furthermore, the skeleton made of porous TiN nanowires on CC provides high electrical conductivity to accelerate charge transport as well as a rough surface to accommodate the Ni nano-clusters. The interaction between the metallic Ni nano-clusters and TiN substrate are demonstrated to promote the activity in OER based on theoretical calculation. This novel electrocatalyst which exhibits superior OER activity and stability in an alkaline electrolyte has large potential in energy conversion and related applications. [ABSTRACT FROM AUTHOR]

• Using CO 2 as the carbon source, the Si/carbon solid-phase doping is realized by introducing the active agent Mg. • The actual particle size of Si in the prepared Si-based anode material is less than 50 nm. • The three-dimensional network structure of carbon provides the most critical buffer layer for Si volume change. SiO 2 is one of the critical raw materials for preparing Si anode. The direct use of porous Si made from SiO 2 in LIBs is challenging. Although carbon cladding can improve the cycling performance of Si anode materials made from SiO 2 , the surface coating cannot address the comminution inside the material during repeated volume deformation. For the first time, we prepared an in-situ doped Si/carbon anode material that uses SiO 2 and CO 2 as Si and carbon sources and Mg as the reduction medium (Mg 2 Si + CO 2 → MgO + Si + C). The in situ embedded carbon completes the nanosizing of Si (less than50 nm) and forms a three-dimensional (3-D) carbon network that enhances electrical conductivity and acts as a buffer layer. After 500 cycles at 0.5 A g−1, the discharge specific capacity is 912 mAh g−1, and the capacity still has 1487 mAh g−1 even at 4 A g−1. The simple method of preparing Si/carbon composite material in situ provides a new idea for modifying Si-based anode material and provides a valuable reference for carbon doping. [ABSTRACT FROM AUTHOR]

Sodium ion batteries (SIBs) are recognized as one of the most promising alternatives for large-scale application due largely to low-cost and sustainable supply-chain. The crucial task is to explore the next generation of cathode materials with satisfactory performances at low cost. In this work, Na 2 FePO 4 F/C nanocomposite (NFPF/C-PG) has been synthesized via liquid route using polyfurfuryl alcohol (PFA) as grain size controller followed by solid-state reaction using glucose as carbon sources. PFA formed in situ polymerization not only prohibits effectively the aggregation of nanoparticle, but also plays a vital role in the construction of carbon network. As a proof-of-concept application, the NFPF/C-PG shows outstanding electrochemical properties as cathode material for sodium ion batteries, which delivers discharge capacities of 73.8 mAh/g with retaining 86.1% of initial capacity over 200 cycles at 1C. Unlabelled Image • Na 2 FePO 4 F/C composite is synthesized with the synergism of polyfurfuryl alcohol. • The Na 2 FePO 4 F nanoparticles are uniformly distributed in graphitized carbon. • NFPF/C-PG shows excellent cycling performance and rate capability. [ABSTRACT FROM AUTHOR]

Graphene, as a typical two-dimensional material, is popular in the design of nanodevices. The interlayer relative sliding of graphene sheets can significantly affect the effective bending stiffness of the few-layered graphene. For restricting the relative sliding, we adopted the atomic shot peening method to bond the graphene sheets together by ballistic C60 fullerenes from its two surfaces. Collision effects are evaluated via molecular dynamics simulations. Results obtained indicate that the fullerenes' incident velocity has an interval, in which the graphene sheet can be bonded after collision while no atoms on the fullerenes escaping from the graphene ribbon after collision. The limits of the interval increase with the layer number. Within a few picoseconds of collision, a stable carbon network is produced at an impacted area. The graphene sheets are bonded via the network and cannot slide relatively anymore. Conclusions are drawn to show the way of potential applications of the method in manufacturing a new graphene-based two-dimensional material that has a high out-of-plane bending stiffness., (© 2021 IOP Publishing Ltd.)

Here, we demonstrate the in situ growth of SnO 2 nanosheets on a freestanding carbonized eggshell membrane (CEM), which provides three-dimensional, bicontinuous electron and ion transport pathways through a massively interconnected carbon fiber skeleton and interpenetrated pore network, respectively. This CEM has other advantages such as the ability to alleviate mechanical stress during cycling as a buffer matrix. When used as an additive-free anode in a sodium-ion battery, SnO 2 nanosheets can realize a complete electrochemical reaction and maintain good cycling stability with the help of a CEM. For instance, SnO 2 nanosheets delivered a high reversible capacity of 656 mA h g -1 in the 5th cycle at 0.1 A g -1 , approaching 98% of its theoretical specific capacity, and maintained a high reversible specific capacity of 420 mA h g -1 after 200 cycles at 0.2 A g -1 .

Large-capacity conversion electrodes are highly required to raise the energy density of batteries. However, their undesired phase segregation and volume expansion during cycling lead to the motivation for nanofabrication and nanochemistry of active species in order to decrease "dead mass" and promote better construction of conductive networks. However, the inactivity of the conductive skeleton and loose nanostructure would compromise the energy density of the electrode. The integration of large-sized (high-density) grains into an electroactive conductive network in a compact way is still a big challenge. Here we report a proof-of-concept prototype consisting of unusual MoS 2 solid bubbles of hundreds of nanometers in size, which are conformally encapsulated by thin-layer carbon. The seamless welding between this carbon coating and the surrounding broader carbon substrate can effectively avoid the peel-off of active species and breakage of the conductive network. This MoS 2 -C composite is achieved by simultaneous self-sulfuration and self-carbonization of a polyoxometalate (POM)-based chelate, and its Li-storage performance is superior to most MoS 2 -based anodes even with ultrathin 2D nanosheets. Partially benefiting from the electroactivity of a dithiooxamide (DTO)-derivate carbon network, the reversible capacity of MoS 2 -C by pyrolyzing the POM-DTO chelate can reach 1500-2000 mAh/g at 0.5-1 A/g even after 700 cycles and be maintained around 1000 mAh/g under as high as 10-20 A/g.

In this letter, we report a facile self-foaming strategy to synthesize Ni 3 C nanoparticles embedded in a porous carbon network (Ni 3 C@PCN) by rationally incorporating a nickel salt precursor into the carbon source. As a novel hydrogen evolution reaction (HER) catalyst, the Ni 3 C@PCN shows superior catalytic activity with an onset potential of -65 mV, an overpotential of 262 mV to achieve 50 mA cm -2 current density, a Tafel slope of 63.4 mV/dec, and durability over 12 h in acidic media. The excellent performance of the novel 3D composite material along with its low-cost merits is suggestive of great potential for scalable electrocatalytic H 2 production.

Sodium ion batteries (NIBs) have been considered as an alternative for Li ion batteries (LIBs). NaTi2(PO4)3 (denoted as NTP) is a superior anode material for NIBs. However, the poor electrochemical performance of NTP resulting from the low electronic conductivity prevents its application. Here, NTP nanoparticles embedded in carbon network (denoted as NTP/C) were fabricated using a simple soft-template method. This anode material exhibits superior electrochemical performance when used as anode electrodes for NIBs, including highly reversible capacity (108 mAh g(-1) at 100 C) for excellent rate performance and long cycle life (83 mAh g(-1) at 50 C after 6000 cycles). The excellent sodium storage property can be resulted from the synergistic effects of nanosized NTP, thinner carbon shell and the interconnected carbon network, leading to the low charge transfer resistance, the large surface area for electrolyte to soak in and enough void to buffer the volume variation during the repeated cycle.