Multi-interface Combination of Bimetallic Selenide and V₄C₃T_x MXene for High-Rate and Ultrastable Sodium Storage Devices

Abstract

Sodium-ion batteries (SIBs) have great potential as electrochemical energy storage systems; however, their commercial viability is limited by the lack of anode materials with fast charge/discharge rates and long lifetimes. These challenges were addressed by developing a multi-interface design strategy using FCSe (FeSe 2 / CoSe 2 ) nanoparticles on V 4 C 3 T x MXene nanosheets as conductive substrates. The heterogeneous interface created between the two materials provided high-speed transport of sodium ions, suppressed the chalking-off of nanoparticles, and improved the cycling stability. Additionally, the Fe−Co bonds generated at the interface effectively relieved mechanical stress, further enhancing the electrode durability. The C@FCSe@V 4 C 3 electrode exhibited high-speed charging and discharging characteristics, and maintained a high specific capacity of 260.5 mAh g −1 even after 15,000 cycles at 10 A g −1 , with a capacity retention rate of 50.2% at an ultrahigh current density of 20 A g −1 . Furthermore, the composite displayed a good cycling capability in the fast discharge and slow charge mode. This demonstrates its promising commercial potential. This multi-interface design strategy provides insights and guidance for solving the reversibility and cycling problems of transformed selenide anode materials.

Interface Engineering Overall Seawater Splitting of Self-Supporting CeOx@NiCo2O4 Arrays

“…Figure a illustrates the charge density distribution for CeO x @NiCo 2 O 4 , with cyan and yellow regions representing electron consumption and accumulation, respectively. It can be observed that the charge density tends to accumulate on the surface of CeO x at the interface between CeO x and NiCo 2 O 4 , indicating significant electron transfers from Co and Ni to CeO x This result further emphasizes the crucial role of hybrid structures in modulating electronic properties, thereby enhancing electrocatalytic performance. , The findings are consistent with the XPS results shown in Figure , which demonstrate positive shifts in the Co 2p and Ni 2p signals. Additionally, Figure b,c presents the densities of electronic states (DOS) for both CeO x @NiCo 2 O 4 and NiCo 2 O 4 .…”

A dual heterostructure enables the stabilization of 1T-rich MoSe2 for enhanced storage of sodium ions

“…1d ). 18 More importantly, compared with that in Cu 2 Se and MoSe 2 , the Cu-d band and Mo-d band in Cu 2 Se@MoSe 2 approached each other and sat closer to the Fermi energy, revealing that an electronic interaction between Cu-d to Mo-d. As displayed in the differential charge density images of Cu 2 Se@MoSe 2 ( Fig. 1e ), depletion of electrons at interfacial Cu atoms and accumulation of electrons at Mo atoms were observed.…”

“…15,16 Metallic selenides with various bandgaps can induce spontaneous electron redistribution at heterointerfaces to generate a built-in electric field (BiEF) that enhances ion transfer. 16–18 Analogically, designing a heterostructure involving MoSe 2 and another selenide could be promising to overcome aforementioned drawbacks, thereby achieving stabilized 1T-MoSe 2 and a BiEF for promoting the transfer of electrons and ions. Such a structure has not been reported for battery materials.…”

Towards metal selenides: a promising anode for sodium-ion batteries

“…However, its improvement in volume expansion and structural stability is limited and requires further exploration. 89,90…”