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Si‐based anode electrodes stand out for its excellent capacity among the numerous anode electrodes for lithium‐ion batteries. However, there is still a problem that the volume expansion from the alloying reaction of Li and Si often leads to structural collapse and rapidly capacity degradation. Here, Si nanoparticles (Si NPs) are coated via metal‐organic frameworks (MOFs) derived skeleton to buffer its volume expansion, thereby improving electrochemical properties. Scanning electron microscopy was applied to revealed morphology and structure of the composite material. The results demonstrate that the structure of the prepared composite is Si NPs encapsulated in the unique carbon skeleton. The as‐prepared Si@MIL‐125‐500 exhibits excellent electrochemical performances with an excellent reversible capacity of 304.3 mAh g−1 at 5 A g−1 even after 400 cycles. In addition, the initial coulombic efficiency (ICE) reached up to 86 %. The improved electrochemical performance could be attributed to the distinctive structure of the carbon coated Si NPs and stable titanium(IV) center site, which has improved the electrical conductivity and cycling stability of Si NPs. Moreover, the empty space inside the MOF's carbon skeleton can release the volume strain of Si during electrochemical process. There is an improvement of electrochemical properties for LIBs due to Si NPs restricted in MIL‐125. [ABSTRACT FROM AUTHOR]

• Mg2+ and Mn2+ co-doped Na 3 V 2 (PO 4) 3 is prepared via a simple high temperature solid method. • Mg2+ and Mn2+ co-doping can propel kinetics behavior and enhance electronic conductivity. • The NVP-(MM) 0.01 exhibits an outstanding rate and cycling performance. • Ex-situ XRD revealed that the structure of NVP-(MM) 0.01 is well maintained after 500 cycles at 10 C. In this article, Mg2+ and Mn2+ co-doped Na 3 V 2 (PO 4) 3 cathode material is prepared, which exhibits enhanced rate capability and long-term cyclic stability for sodium-ion batteries. [Display omitted] Na 3 V 2 (PO 4) 3 with open 3D framework structure is perceived as the most potential cathode material for sodium-ion batteries (SIBs). Nevertheless, its electrochemical properties are generally restricted by the larger radius of Na+ and the intrinsic poor electrical conductivity. Herein, we adopt a unique bimetallic doping strategy to prepare Mg2+ and Mn2+ co-doped Na 3 V 2−x (Mg 0.5 Mn 0.5) x (PO 4) 3 [NVP-(MM) x (x = 0, 0.01, 0.02)] through a high temperature solid state reaction. The as-prepared NVP-(MM) 0.01 presents a high initial discharge capacity of 107.7 mA h g−1 at 1 C. Furthermore, NVP-(MM) 0.01 displays a highly rate capability (75.5 mA h g−1 at 15 C) and excellent cycling performance (71 mA h g−1 after 1000 cycles at 20 C). Electrochemical results exhibit that Mg2+ and Mn2+ co-doped with appropriate proportion can enhance the electronic conductivity and sodium storage kinetics process of Na 3 V 2 (PO 4) 3 effectively. Our work provides a novel idea to construct high performance SIBs via a bimetallic co-doped strategy. [ABSTRACT FROM AUTHOR]

Eelectrochemical performance of fabricated asymmetric supercapacitor. Transition metal dichalcogenides (TMDs) have been considered as the promising energy storage materials due to their unique crystalline structure. In this work, the VSe 2 nanoparticles are vertically anchored on N -doping carbon (NC) hollow nanosphere (VSe 2 @NC) for aqueous energy application. The electrochemical measurements indicate that the VSe 2 @NC electrode exhibits outstanding electrochemical properties with high specific capacitance and excellent cycling life. Moreover, the asymmetric supercapacitor was assembled by using VSe 2 @NC cathode and activated carbon anode. It shows high energy density of 85.41 Wh Kg−1 at a power density of 701.99 W Kg−1, and high-stable cycling performance of 90% retention after 2000 cycles. The superior properties are attributed to the particular hollow structure design, which accommodates both the high specific capacity of VSe 2 and the desired electrical conductivity of N -doping carbon sphere template. [ABSTRACT FROM AUTHOR]

• The Co 3 O 4 is modified by deposition CoNiS nanowires. • CoNiS improves the chemical stability and electrical conductivity of Co 3 O 4. • Co 3 O 4 @CoNiS exhibits high specific capacity. • Core-shell structure provides more active sites and stable structure. • Co 3 O 4 @CoNiS//NOPC supercapacitor delivers an outstanding cyclic stability. Tricobalt tetroxide (Co 3 O 4) with high theoretical capacity has been considered as a promising material for supercapacitors. However, the poor electrical conductivity and poor capacity retention hinder its further larger-scale application. Besides, a series of metal sulfides shows good thermal stability, mechanical stability and electrical conductivity. Here, hierarchical core-shell nanostructure is successfully synthesized by coating the Co 3 O 4 nanowires with highly conductive CoNiS (Co 3 O 4 @CoNiS) by a facile two-step method of hydrothermal treatment and succeeding electrodeposition. And the core-shell structure presents high electrical conductivity, discharge capacity and good cycle life. The as-prepared Co 3 O 4 @CoNiS exhibited a high specific capacity of 1153.75 C g−1, which is 1.97 times as much as that of Co 3 O 4. Furthermore, an asymmetric supercapacitor (ASC) was assembled by using the N/O co-doped porous carbon (NOPC) as negative electrode and the as-prepared Co 3 O 4 @CoNiS as positive electrode, which showed a high energy density of 46.95 Wh kg−1 at the power density of 400 W kg−1 and an ultra-stable capacity retention with 95.6% for 20,000 cycles. The cyclic stability of similar work is lower than that of our work, which provides a reference for the preparation of electrode materials with long-term cyclic stability. [ABSTRACT FROM AUTHOR]