Search

[Display omitted] • Multifunctional Co 9 S 8 @CNSs/CNFs flexible self-supporting electrode is designed for Sodium-ion batteries. • The advantages of multi-stage structural synergistic composites are illustrated at the electrode scale. • In-depth analysis of electrode electrochemical reaction kinetics and de-/sodiation mechanism. • High sodium storage half-cells and stable full cell capacity with self-supporting electrodes are achieved. Transition metal sulfides (TMSs) are considered as promising anodes for sodium-ion batteries (SIBs) due to their high theoretical capacity and low cost. However, TMSs suffer from massive volume expansion, slow sodium-ion diffusion kinetics, and poor electrical conductivity, which severely restrict their practical application. Herein, we design self-supporting Co 9 S 8 nanoparticles embedded carbon nanosheets/carbon nanofibers (Co 9 S 8 @CNSs/CNFs) as anode materials for SIBs. The electrospun carbon nanofibers (CNFs) provide continuous conductive networks to accelerate the ion and electron diffusion/transport kinetics, while MOFs-derived carbon nanosheets (CNSs) buffer the volume variation of Co 9 S 8 , consequently improving the cycle stability. Benefitting from the unique design and pseudocapacitive features, Co 9 S 8 @CNSs/CNFs deliver a stable capacity of 516 mAh g−1 at 200 mA g−1 and a reversible capacity of 313 mAh g−1 after 1500 cycles at 2 A g−1. Note that, it also displays excellent sodium storage performance when assembled into a full cell. The rational design and excellent electrochemical properties endow Co 9 S 8 @CNSs/CNFs with the potential stepping into commercial SIBs. [ABSTRACT FROM AUTHOR]

A series of core-triple-shelled GCNF/PANI/NCO nanostructures have been fabricated via a facile strategy. Taking full advantage of the free-standing architecture of graphene-coated electrospun carbon nanofibers (GCNF), high conductivity and flexibility of the polyaniline (PANI) layers, and abundant active sites of nickel carbonate hydroxide (Ni 2 (CO 3)(OH) 2) nanosheets, the optimal electrode exhibits a high specific capacitance of 1565F g−1 at 1 A/g, which exceeds almost all of the reported nickel carbonate hydroxide-based electrodes in literatures. A hybrid supercapacitor delivers a high energy density of 35.4 Wh kg−1@750 W kg−1 and a long cycle lifespan. This strategy enables the controllable synthesis of core-triple-shelled hierarchical materials applicable to diverse electrochemical applications. [Display omitted] • We prepared the core-triple-shelled GCNF/PANI/NCO fiber-based films via a new route. • The optimal electrode exhibits high electrochemical properties via joint actions. • A hybrid supercapacitor displays large specific capacities and high energy density. • This strategy provides a new way to synthesize other core-triple-shelled materials. Designing novel efficient electrode materials with controlled hierarchical structure and composition for advanced supercapacitors remains a great challenge. Herein, a core-triple-shelled hierarchical GCNF/PANI/NCO nanostructure has been designed and fabricated by sequential growth of the conductive polyaniline (PANI) layers and nickel carbonate hydroxide (Ni 2 (CO 3)(OH) 2) nanosheets on the graphene-coated electrospun carbon nanofibers (GCNF) via a facile wet-chemical strategy. Taking full advantage of the free-standing architecture of graphene-coated electrospun carbon nanofibers, high conductivity and flexibility of the PANI layers, and abundant active sites of Ni 2 (CO 3)(OH) 2 nanosheets, the optimal GCNF/PANI/NCO (2 h) electrode exhibits a high specific capacitance of 1565F g−1 at 1 A/g and enhanced rate capability, which are higher than those of the GCNF, GCNF/PANI, and GCNF/NCO (2 h) electrodes at the same situation, and also exceeds most of the reported nickel carbonate hydroxide-based electrodes in literature. The superior performance should be mainly ascribed to the collaborative contribution of each component. Moreover, a self-assembled GCNF/PANI/NCO//AC hybrid supercapacitor delivers a high energy density of 35.4 Wh kg−1@750 W kg−1 and a long cycle lifespan. This strategy enables the controllable synthesis of core-triple-shelled hierarchical materials applicable to advanced electrochemical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Potassium-ion batteries (PIBs) have attracted enormous attention due to the increasing lithium battery cost, but their development is still in the pre-mature stage due to the limited selection of electrodes. Herein, a free-standing current-collector-integrated electrode, composed of mixed-phase WS 2 nanosheets with nitrogen-doped multichannel carbon nanofibers (N -MCNFs) membrane, is reported for high-performance potassium ion batteries anode. Benefiting the unique multichannel carbon nanostructure as a current collector-integrated electrode as well as mixed-phase lamellar structure WS 2 for enhanced potassium ion entry, the 1T/2H-WS 2 / N -MCNFs hybrid current-collector-free anode delivers an outstanding areal capacity of 2.88 mAh cm−2 (corresponding to 411 mAh/g based on the mass of both electrode and current collector) at a current of 0.7 mA cm−2 as well as long-term cycling stability for over 1000 cycles at a high current of 14 mA cm−2, surpassing the current state-of-art PIB anode. It is believed that our findings based on the high energy current collector integrated electrode at high mass loading would boost future research on practical metal ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] Potassium-ion batteries (PIBs) have attracted enormous attention due to the increasing lithium battery cost, but their development is still in the pre-mature stage due to the limited selection of electrodes. Herein, a free-standing current-collector-integrated electrode, composed of mixed-phase WS 2 nanosheets with nitrogen-doped multichannel carbon nanofibers (N -MCNFs) membrane, is reported for high-performance potassium ion batteries anode. Benefiting the unique multichannel carbon nanostructure as a current collector-integrated electrode as well as mixed-phase lamellar structure WS 2 for enhanced potassium ion entry, the 1T/2H-WS 2 / N -MCNFs hybrid current-collector-free anode delivers an outstanding areal capacity of 2.88 mAh cm−2 (corresponding to 411 mAh/g based on the mass of both electrode and current collector) at a current of 0.7 mA cm−2 as well as long-term cycling stability for over 1000 cycles at a high current of 14 mA cm−2, surpassing the current state-of-art PIB anode. It is believed that our findings based on the high energy current collector integrated electrode at high mass loading would boost future research on practical metal ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] With the increasing energy and environmental crisis, exploring convenient and general strategies for constructing of highly active, stable, and cost-effective bifunctional electrocatalysts for overall water splitting are exceedingly desirable yet still challenging. Herein, 3D hierarchical mesoporous cobalt phosphide embedded N-doped carbon nanoflowers (CoP@NCNFs) are successfully constructed with ultrathin nanosheets by phosphating of the cobalt coordination polymer nanoflowers (CoCPNFs). By virtue of their unique architecture and particular composition, the obtained CoP@NCNFs reveal extraordinary performance with ultralow overpotentials and small Tafel slopes for both OER (291 mV at 10 mA cm−2; 75 mV dec−1) and HER (166 mV at 10 mA cm−2; 76 mV dec−1) in alkaline medium. In particular, CoP@NCNFs can act as both anode and cathode to perform overall water splitting, and the assembled device only needs a cell voltage as low as 1.59 V to achieve the current density of 10 mA cm−2. Simultaneously, the CoP@NCNFs also exhibit admirable durability (at least 15 h) throughout the water splitting process. These remarkable electrocatalytic performances could be attributed to the synergistic effect of highly active CoP NPs and conductive mesoporous N-doped carbon nanosheets, which effectively improved the surface contact between catalyst and electrolyte, mass diffusion, and stability. [ABSTRACT FROM AUTHOR]