Red phosphorus (P) has been recognized as a promising material for lithium/sodium-ion batteries (LIBs/SIBs) because of their high theoretical capacity. However, tremendous volume variation and low conductivity limit its widespread applications. Hence, we design and synthesize uniformly distributed honeycomb-like hierarchical micro–mesoporous carbon nanospheres (HHPCNSs) with ultralarge pore volume (3.258 cm3 g–1) on a large scale through a facile way. The large pore volume provides enough space for loading of P and the expansion of P, and the uniform distribution of the micro–mesopores enables the red P to load uniformly. The resulting HHPCNSs/P composite exhibits extremely high capacity (2463.8 and 2367.6 mA h g–1 at 0.1 A g–1 for LIBs and SIBs, respectively), splendid rate performance (842.2 and 831.1 mA h g–1 at 10 A g–1 for LIBs and SIBs, respectively) and superior cycling stability (1201.6 and 938.4 mA h g–1 at 2 and 5 A g–1 after 1000 cycles for LIBs and 1269.4 and 861.8 mA h g–1 at 2 and 5 A g–1 after 1000 cycles for SIBs, respectively). More importantly, when coupled with LiFePO4 and Na3V2(PO4)3 cathode, lithium/sodium-ion full batteries display high capacity and superior rate and cycling performances, revealing the practicability of the HHPCNSs/P composite. The exceptional electrochemical performance is caused by the honeycomb-like carbon network with ultralarge pore volume, uniformly distributed hierarchical micro–mesoporous nanostructure, outstanding electronic conductivity, and excellent nanostructural stability, which is much better than currently reported P/C materials for both LIBs and SIBs.

The solid−solid conversion of Li 2 S 2 to Li 2 S is a crucial and rate-controlling step that provides one-half of the theoretical capacity of lithium−sulfur (Li−S) batteries. The catalysts in the Li−S batteries are often useless in the solid−solid conversion due to the poor contact interfaces between solid catalysts and insoluble solid Li 2 S 2 . Considering that ultrafine nanostructured materials have the properties of quantum size effects and unconventional reactivities, we design and synthesize for the pomegranate-like sulfur

Recently, adopting carbon coating has drawn considerable attention for increasing the electrical conductivity and enhancing the stability of the electrode materials as elastic buffer supports upon cycling to improve the electrochemical performance. [27][28][29][30][31] Even through the volume changes may be effectively controlled by flexible substrates, this strategy is still limi ted in improving specific capacity and rate performance. Nanoengineering of ultrafine nanostructure (ultrafine nanoparticles or ultrafine nanosized subunits) has become the most powerful mean to tackle above challenge because they can increase the electrodeelectrolyte contact area, lower the absolute volume change, and shorten the distance for lithium-ion diffusion within the particles. [32,33] For instance, 3D mesoporous Co 3 O 4 networks composed of small Co 3 O 4 nanoparticles (5-10 nm) synthesized by Naiqin Zhao exhibit high specific capacity (1033 mA h g −1 at 0.1 A g −1 ) and remarkable rate capability. [34] Furthermore, robust and favorable ultrafine secondary nanoparticles would effectively accommodate the severe volume variation upon cycling and prevent self-aggregation of the ultrafine nanoscale subunits, thus leading to improved capacity retention and rate capability. For example, polydopamine-coated SnO 2 nanocrystals comprising SnO 2 nanoparticles (diameter ≈ 5 nm) developed by Lin and co-workers display excellent rate capability. [35] Nevertheless, the existing synthetic methods can only fabricate the ultrafine nanoparticles with exposed or mosaic structure which have disadvantages of inevitable aggregation and unstable nanostructure during long-term cycling; moreover, they are unsuitable for large-scale production. Hence, it is a great challenge to design and synthesize ultrafine carbon coating TMO subunit through a facile and one-pot method on a large scale.Along these lines, we develop a facile and novel one-pot approach for the first time to synthesize a series of highly uniform pomegranate-like TMO@nitrogen-doped carbon nanoclusters (TMO@N-C NCs) with a large scale production, which are organized by numerous of ultrafine TMO@N-C subunits (diameter ≈ 4 nm). This approach has been demonstrated to synthesize various pomegranate-like TMO@N-C NCs, including simple oxides such as Fe 3 O 4 , Mn 3 O 4 , NiO, and ZnO. Taking pomegranate-like Fe 3 O 4 @N-C NCs as an example, the pomegranate-like Fe 3 O 4 @N-C NCs with this unique nanostructure show excellent cycle stability and superior rate capacity Uniform pomegranate-like nanoclusters (NCs) organized by ultrafine transition metal oxide@nitrogen-doped carbon (TMO@N-C) subunits (diameter ≈ 4 nm) are prepared on a large scale for the first time through a facile, novel, and one-pot approach. Taking pomegranate-like Fe 3 O 4 @N-C NCs as an example, this unique structure provides short Li + /electron diffusion pathways for electrochemical reactions, structural stability during cycling, and high electrical conductivity, leading to superior electrochemical performance. The resulting...

electrochemical water splitting is an advocated way to meet the requirement for future fuel applications. [3] But its shortcomings, such as the considerable overpotential and sluggish anodic oxygen evolution reaction (OER) kinetics, still remain. To give rise to energy-saving H 2 production, using more readily oxidized molecules to replace the formidable OER may be a feasible solution to overcome this limitation. [4,5] Following this strategy, several molecules such as glycerol, [6] urea, [2,7] hydrazine, [8] have been recently developed. Using urea electrolysis instead of water splitting can not only offer a prospect of wastewater purification, but also change the thermodynamic potential from 1.23 to just 0.37 V. [5] However, the complex 6e − transfer process in the half-reaction causes the urea oxidation reaction (UOR) to suffer from inherent kinetic retardation. [9] Therefore, to promote the anodic urea oxidation process, highly efficient catalysts are actually required to boost the intrinsically sluggish UOR kinetics. Vanadium (V)-based electrocatalysts (such as VS 2 , [10,11] VN, [12-15] VP, [16] and V 2 O 3 [17-19]) are conducive for its application in catalysis fields, because of its more valence state diversity. Catalytic activities of the vanadium-based electrocatalyst are closely related with its electronic structure. [16] Thus, it is widely accepted that adjusting the behavior of electrons and phonons more precisely is the key to optimizing the catalyst performance. [16] Schottky heterojunction, formed at the semiconductor metal interface, could generate the built-in electric field and enhance the charge transportation as well as separation. [20-22] To balance the differences of Fermi levels between semiconductor and metal sides, charge flow would spontaneously transfer across the interface, leading to form the stable local nucleophilic/electro region. [20] Hence, preparing ingenious V-based Schottky catalyst is the proof-of-concept way to simultaneously promote the hydrogen evolution reaction (HER) and UOR activities. For example, Fu et al. reported that construction of heterointerfaces of Ni 3 NVN and Ni 2 PVP 2 can improve the HER and OER activities significantly. [16] However, most of the reported works only focus on the construction The Mott-Schottky heterojunction formed at the interface of ultrafine metallic Ni and semiconducting V 2 O 3 nanoparticles is constructed, and the heterojunctions are "knitted" into the tulle-like monolayer nanosheets on nickel foam (NF). The greatly reduced particle sizes of both Ni and V 2 O 3 on the Mott-Schottky heterojunction highly enhance the number of Schottky heterojunctions per unit area of the materials. Moreover, arranging the heterojunctions into the monolayer nanosheets makes the heterojunctions repeat and expose to the electrolyte sufficiently. The Schottky heterojunctions are like countless selfpowered charge transfer workstations embedded in the tulle-like monolayer nanosheets, promoting maximum of the materials to participate into the electron trans...

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