Search

NiCo 2 S 4 as a promising anode material for sodium ion batteries (SIBs) with rich redox potential and high theoretical specific capacity, but suffers the poor conductivity and severe volume expansion. The electrode materials with a three-dimensional (3D) framework can facilitate the migration of ions/electrons, enhance structural stability, and alleviate the volume expansion during charging/discharging. Herein, we report the NiCo 2 S 4 nanoparticles anchored on a 3D interpenetrating framework consisting of graphene nanosheets (GNs) and carbon nanotubes (CNTs) to solve the above issues. Benefiting from the structural stability and superior conductivity in special 3D structure, the as-prepared NCS@GNs@CNTs electrode delivers a high initial discharge/charge capacity (558.1/538.8 mAh g1 at 100 mA g−1), superior cyclic stability (362.8 mAh g−1 after 100 cycles at 200 mA g−1) and an excellent rate capability (311.8 mAh g−1 at 5000 mA g−1). Furthermore, the sodium-ion full-cell Na 3 V 2 (PO 4) 3 @C-NCS@GNs@CNTs test demonstrates that NCS@GNs@CNTs exhibits good cycling stability and further illustrates the possibility in practical applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries appear to be one of the most promising energy-storage devices owing to the unparalleled theoretical specific energy, relatively inexpensive price and abundant resources. Despite these attractive features, the practical performances of sulfur cathode still remain a lot of challenges, such as the electrical insulating nature of S and Li 2 S, huge volume change during cycling, notorious shuttle effect of lithium polysulfide intermediates (LiPSs), sluggish redox kinetics and construction of thick electrodes with high sulfur loading. Here, CoFe 2 O 4 nanoparticles anchored on the carbon nanotube (CNT) paper is proposed as free-standing sulfur host to address the issues. The cross-linking CNT network can serve as conductive matrix and accommodate volume change upon cycling simultaneously. Meanwhile, the CoFe 2 O 4 nanoparticles are capable of effectively anchoring LiPSs to suppress the shuttle effect and accelerating LiPSs conversion to boost redox kinetics. Moreover, the free-standing paper electrode without any binder is conducive to constructing stable cathode with high sulfur loading. In consequence, the well-designed S/CoFe 2 O 4 /CNT paper cathodes deliver impressive electrochemical performance, demonstrating an initial discharge capacity of 755.3 mAh g−1 and remaining a high reversible capacity of 642.6 mAh g−1 after 400 cycles at 2 C with an inconspicuous decay of 0.04% per cycle. The bimetallic oxide CoFe 2 O 4 nanoparticles anchored on the carbon nanotube paper is proposed as free-standing sulfur host with enhanced polysulfide trapping and catalytic effects for advanced Li-S batteries. [Display omitted] • Binder-free host realizes high sulfur loading and energy density for Li-S battery. • CoFe 2 O 4 /CNT paper inhibits the polysulfide shuttling via strong chemical interaction. • CNT-anchored CoFe 2 O 4 catalytically promotes the polysulfide conversion kinetics. • The Li-S battery with S/CoFe 2 O 4 /CNT cathode exhibits enhanced capacity and stability. [ABSTRACT FROM AUTHOR]