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Sub‐nanoclusters with ultra‐small particle sizes are particularly significant to create advanced energy storage materials. Herein, Sn sub‐nanoclusters encapsulated in nitrogen‐doped multichannel carbon matrix (denoted as Sn‐SCs@MCNF) are designed by a facile and controllable route as flexible anode for high‐performance potassium ion batteries (PIBs). The uniformly dispersed Sn sub‐nanoclusters in multichannel carbon matrix can be precisely identified, which ensure us to clarify the size influence on the electrochemical performance. The sub‐nanoscale effect of Sn‐SCs@MCNF restrains electrode pulverization and enhances the K+ diffusion kinetics, leading to the superior cycling stability and rate performance. As freestanding anode in PIBs, Sn‐SCs@MCNF manifests superior K+ storage properties, such as exceptional cycling stability (around 331 mAh g−1 after 150 cycles at 100 mA g−1) and rate capability. Especially, the Sn‐SCs@MCNF||KFe[Fe(CN)6] full cell demonstrates impressive reversible capacity of around 167 mAh g−1 at 0.4 A g−1 even after 200 cycles. Theoretical calculations clarify that the ultrafine Sn sub‐nanoclusters are beneficial for electron transfer and contribute to the lower energy barriers of the intermediates, thereby resulting in promising electrochemical performance. Comprehensive investigation for the intrinsic K+ storage process of Sn‐SCs@MCNF is revealed by in situ analysis. This work provides vital guidance to design sub‐nanoscale functional materials for high‐performance energy‐storage devices. [ABSTRACT FROM AUTHOR]

Lithium metal anodes are widely regarded as the ideal candidate for the next generation of high‐energy‐density lithium batteries. Here, a 3D host made of lithiophilic Mo2C clusters‐embedded carbon nanofibers (Mo2C@CNF) is developed. The uniformly dispersed clusters and large specific surface areas of Mo2C@CNF provide numerous nucleation sites for lithium deposition. Mo2C clusters exhibit ultralow nucleation overpotential compared to MoO2, which is also supported by density functional theory calculations. Furthermore, the transition metal element serves as a catalyst for the formation of a stable and robust solid electrolyte interphase layer containing LiF on Mo2C@CNF, effectively mitigating the occurrence of dead lithium and enhancing the Coulombic efficiency during prolonged operation. As a result, the Mo2C@CNF composite delivers superior electrochemical performance (>1600 h) at 1 mA cm−2 and lower nucleation overpotential (13 mV) for lithium plating. The Li/Mo2C@CNF anode coupled with the commercial LiFePO4 cathode exhibits excellent cycling stability (300 cycles at 1 C) and high rate capability at low N/P ratios. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO2) was considered as a promising alternative to commonly used graphite anode in energy storage devices thanks to its superior specific capacity. However, its electrochemical property was severely limited due to the inherent poor conductivity and drastic volume variation during the charging/discharging process. To overcome this disadvantage, we grew Sn-MOF directly on graphene oxide (GO) layers to synthesize a double carbon conductive network-encapsulated SnO2 nanoparticles (SnO2/C/rGO) via a facile solvothermal method. During the process, Sn-MOF skeleton transformed into porous carbon shells, in which nanosized SnO2 particles (~8nm) were embedded, while GO template was reduced to highly conductive rGO layer tightly wrapping the SnO2/C particles. This double-carbon structure endowed SnO2/C/rGO anode with enhanced specific capacity and rate property both in lithium ion batteries (LIB) and sodium ion batteries (SIB). The SnO2/C/rGO anode showed a highly reversible specific capacity of 1038.3 mAh g−1 at 100 mA g−1, and maintained a stable capacity of 720.2 mAh g−1 (70.1%) under 500 mA g−1 after 150 cycles in LIBs. Similarly, highly reversible capacity of 350.7 mAh g−1 (81.1%) under 100 mA g−1 after 150 cycles was also achieved in SIBs. This work provided a promising strategy in improving the electrochemical properties of SnO2 nanoparticles (NPs), as well as other potential anode materials suffering from huge volume change and poor conductivity. [ABSTRACT FROM AUTHOR]

Two‐dimensional metal sulfides and their hybrids are emerging as promising candidates in various areas. Yet, it remains challenging to synthesize high‐quality 2D metal sulfides and their hybrids, especially iso‐component hybrids, in a simple and controllable way. In this work, a low‐temperature selective solid‐liquid sulfidation growth method has been developed for the synthesis of CuS nanoflakes and their hybrids. CuS nanoflakes of about 20 nm thickness and co‐component hybrids CuOx/CuS with variable composition ratios derived from different sulfidation time are obtained after the residual sulfur removal. Besides, benefiting from the mild low‐temperature sulfidation conditions, selective sulfidation is realized between Cu and Fe to yield iso‐component FeOx/CuS 2D nanoflakes of about 10–20 nm thickness, whose composition ratio is readily tunable by controlling the precursor. The as‐synthesized FeOx/CuS nanoflakes demonstrate superior lithium storage performance (i. e., 707 mAh g−1 at 500 mA g−1 and 627 mAh g−1 at 1000 mA g−1 after 450 cycles) when tested as anode materials in LIBs owing to the advantages of the ultrathin 2D nanostructure as well as the lithiation volumetric strain self‐reconstruction effect of the co‐existing two phases during charging/discharging processes. [ABSTRACT FROM AUTHOR]

Owing to the high specific capacity and energy density, metal oxides have become very promising electrodes for lithium‐ion batteries (LIBs). However, poor electrical conductivity accompanied with inferior cycling stability resulting from large volume changes are the main obstacles to achieve a high reversible capacity and stable cyclability. Herein, a facile and general approach to fabricate SnO2, Fe2O3 and Fe2O3/SnO2 fibers is proposed. The appealing structural features are favorable for offering a shortened lithium‐ion diffusion length, easy access for the electrolyte and reduced volume variation when used as anodes in LIBs. As a consequence, both single and hybrid oxides show satisfactory reversible capacities (1206 mAh g−1 for Fe2O3 and 1481 mAh g−1 for Fe2O3/SnO2 after 200 cycles at 200 mA g−1) and long lifespans. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO 2 ) was considered as a promising alternative to commonly used graphite anode in energy storage devices thanks to its superior specific capacity. However, its electrochemical property was severely limited due to the inherent poor conductivity and drastic volume variation during the charging/discharging process. To overcome this disadvantage, we grew Sn-MOF directly on graphene oxide (GO) layers to synthesize a double carbon conductive network-encapsulated SnO 2 nanoparticles (SnO 2 /C/rGO) via a facile solvothermal method. During the process, Sn-MOF skeleton transformed into porous carbon shells, in which nanosized SnO 2 particles (~8nm) were embedded, while GO template was reduced to highly conductive rGO layer tightly wrapping the SnO 2 /C particles. This double-carbon structure endowed SnO 2 /C/rGO anode with enhanced specific capacity and rate property both in lithium ion batteries (LIB) and sodium ion batteries (SIB). The SnO 2 /C/rGO anode showed a highly reversible specific capacity of 1038.3 mAh g -1 at 100 mA g -1 , and maintained a stable capacity of 720.2 mAh g -1 (70.1%) under 500 mA g -1 after 150 cycles in LIBs. Similarly, highly reversible capacity of 350.7 mAh g -1 (81.1%) under 100 mA g -1 after 150 cycles was also achieved in SIBs. This work provided a promising strategy in improving the electrochemical properties of SnO 2 nanoparticles (NPs), as well as other potential anode materials suffering from huge volume change and poor conductivity., (© 2021 IOP Publishing Ltd.)

Two-dimensional metal sulfides and their hybrids are emerging as promising candidates in various areas. Yet, it remains challenging to synthesize high-quality 2D metal sulfides and their hybrids, especially iso-component hybrids, in a simple and controllable way. In this work, a low-temperature selective solid-liquid sulfidation growth method has been developed for the synthesis of CuS nanoflakes and their hybrids. CuS nanoflakes of about 20 nm thickness and co-component hybrids CuO x /CuS with variable composition ratios derived from different sulfidation time are obtained after the residual sulfur removal. Besides, benefiting from the mild low-temperature sulfidation conditions, selective sulfidation is realized between Cu and Fe to yield iso-component FeO x /CuS 2D nanoflakes of about 10-20 nm thickness, whose composition ratio is readily tunable by controlling the precursor. The as-synthesized FeO x /CuS nanoflakes demonstrate superior lithium storage performance (i. e., 707 mAh g -1 at 500 mA g -1 and 627 mAh g -1 at 1000 mA g -1 after 450 cycles) when tested as anode materials in LIBs owing to the advantages of the ultrathin 2D nanostructure as well as the lithiation volumetric strain self-reconstruction effect of the co-existing two phases during charging/discharging processes., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Owing to the high specific capacity and energy density, metal oxides have become very promising electrodes for lithium-ion batteries (LIBs). However, poor electrical conductivity accompanied with inferior cycling stability resulting from large volume changes are the main obstacles to achieve a high reversible capacity and stable cyclability. Herein, a facile and general approach to fabricate SnO 2 , Fe 2 O 3 and Fe 2 O 3 /SnO 2 fibers is proposed. The appealing structural features are favorable for offering a shortened lithium-ion diffusion length, easy access for the electrolyte and reduced volume variation when used as anodes in LIBs. As a consequence, both single and hybrid oxides show satisfactory reversible capacities (1206 mAh g -1 for Fe 2 O 3 and 1481 mAh g -1 for Fe 2 O 3 /SnO 2 after 200 cycles at 200 mA g -1 ) and long lifespans., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Cost-effective metal-based nanostructured hybrids have been widely dedicated to potential energy storage and conversion applications. Herein, we develop a facile methodology for the synthesis of precise carbon-confined hybrid nanostructures by stereoselective assembly accompanied by catalytic pyrolysis. Polyacrylonitrile fiber films favors not only metal-polymer coordination, but also oriented assembly to ensure the well-defined nanostructure of the carbon hybrids. During chemical vapor deposition (CVD), cobalt-nanoparticle-catalyzed growth of carbon-nanotube branches driven by organic molecules (e.g. melamine) delivers hierarchical carbon hybrids. The resulting carbon hybrids exhibit outstanding electrochemical performance for metal-ion batteries, for example, a high specific capacity of 680 mAh g -1 after 320 cycles (Li-storage) and 220 mAh g -1 after 500 cycles (Na-storage) without decay., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)