Search

[Display omitted] • Fe 2 O 3 /MoC@NG shows excellent rate performance and large-current long-cycle stability. • Pseudocapacitance control is the major charge–discharge mechanism. • Fe 2 O 3 /MoC@NG shows 21-time enhanced Li+ ion diffusion kinetics compared with Fe 2 O 3 @NG. • Stabilization of Li-DIBs anode structure by heterointerface bonding of Fe 2 O 3 /MoC@NG. • The transport paths of PF 6 − and Li+ ions in dual-ion batteries are studied. Lithium dual-ion batteries (Li-DIBs) technology is expected to become a leader in replacing lithium-ion batteries (LIBs) to carry out high energy/power density energy storage devices. Unfortunately, the sluggish electrochemical reaction kinetics of anode materials critically restricts their practical development. Here, a Li-DIBs is proposed by using a three-dimensional (3D) structure composed of Fe 2 O 3 /MoC heterostructure nanoparticals embedded in a hierarchical mesoporous nitrogen-doped reduction graphene oxide (Fe 2 O 3 /MoC@NG) as the anode, which has low Li+ ion diffusion barrier (0.098 eV), high Li+ ion diffusion coefficient (4.99 × 10−11 cm2 s−1) and remarkable rate property (879.2 mA h g−1 at 10 A g−1), and choosing nano-graphite as the cathode. Originating from the respective strengths of Fe 2 O 3 /MoC@NG anode and the nano-graphite cathode, the as-constructed Li-DIBs full battery displays high reversible capacity and prominent rate property (103.9 mA h g−1 at 0.05 A g−1 and 48.9 mA h g−1 at 2 A g−1). Specifically, taking advantage of density functional theory (DFT) calculations, the exact paths of PF 6 − ion intercalation into graphite cathode and Li+ ion diffusion into Fe 2 O 3 /MoC@NG anode is obtained, namely PF 6 − ion transmits along the (0 0 2) face of nano-graphite and Li+ ion diffuses along the heterointerface of Fe 2 O 3 /MoC@NG. [ABSTRACT FROM AUTHOR]

High-performance flexible sodium-ion batteries based on carbon sphere-supported hierarchical Nb2CTx MXene/MoS 2 composites, which excellent specific capacity, cycle stability and rate performance. It has a specific capacity of 196 mAh g-1 at a current density of 20 A g-1. In addition, this design scheme can also be extended to other application scenarios. [Display omitted] • Hollow carbon sphere could make electrode three-dimensional. • MXene-bonded 3D hierarchical structure could reduce the charge transfer path. • Nb 2 CT x /MoS 2 @CS anode have outstanding cycle stability for Na ion storage. • MXene-bonded electrode have certain flexibility. Hand-made Nb 2 CT x /MoS 2 @CS//NVP full battery could reach to 90° bending. Sodium-ion batteries, as a promising alternative to the lithium-ion battery, have attracted extensive attention. However, due to the larger ion radius and higher standard reduction potential, the sodium-ion batteries still face poor cycle stability and relatively low energy density problems. In this work, a carbon sphere-supported Nb 2 CT x MXene/MoS 2 hierarchical structure has been designed and synthesized through hydrothermal and electrostatic self-assembly methods. The design strategy successfully improves the utilization efficiency of the MoS 2 carbon sphere as a support skeleton and reducing the diffusion path length of Na ions, leading to an improved specific capacity and rate performance. Moreover, Nb 2 CT x sheets also effectively inhibit the capacity attenuation caused by MoS 2 shedding, thus achieving the long cycle life of the sodium-ion battery. As a result, the carbon-supported MXene/MoS 2 anode delivers an ultrahigh reversible capacity, long cycling stability, and superior capacity retention rate. Notably, the carbon-supported MXene/MoS 2 anode can also obtain a considerable capacity of 196 mAh g−1 at a current density of 20 A g−1. The full cell of SIBs was assembled, and the flexibility of the battery was tested. The density functional theory simulation results show that the sodium ion has a smaller diffusion barrier under this material design strategy. [ABSTRACT FROM AUTHOR]