Core–Shell CoSe₂/WSe₂ Heterostructures@Carbon in Porous Carbon Nanosheets as Advanced Anode for Sodium Ion Batteries

Abstract

Therefore, in response to the above issues, the most urgent and crucial task is to develop novel anode materials with special crystal design, aiming to improve the kinetics of sodiation and desodiation, which mainly comprises the finding of new materials and the structural design and morphology control of materials. [5] So far, transition metal chalcogenides, consisting of transition metal oxides, [6] transition metal sulfides, [7] and transition metal selenides, [8] have been considered as promising anode materials for SIBs due to their high theoretical capacities and conductivities, unique layered structures and favorable cycling stabilities. [9,10] In particular, transition metal selenides, such as MoSe 2 , [11] CoSe 2 , [12] WSe 2 , [13] and FeSe 2 , [14] have drawn great attention, ascribed to their relatively small bandgaps with enhanced conductivities. Additionally, compared with transition metal oxides/sulfides, transition metal selenides have slightly larger and weaker metal-selenium bonds, which can be helpful for the insertion and extraction of sodium. [15] For example, Ali et al. reported transition metal selenide (Fe 2 CoSe 4 ) and transition metal sulfide (Fe 2 CoS 4 ) as the electrode for SIBs, Fe 2 CoSe 4 exhibited batter battery performance (614.5 mA h g −1 ) than Fe 2 CoS 4 (335.8 mA h g −1 ) at 1 A g −1 after 100 cycles. [16] Among transition metal selenides, CoSe 2 has drawn great attention as anode material for SIBs because of its unique structure of the cubic pyrite-type or orthorhombic marcasite-type in which two selenium atoms are inserted into the crystal lattice of Co. [17] It has been proved that this unique structure is conducive to the diffusion of large-size sodium ions during the charge/discharge process. WSe 2 , as a 2D selenide, has advantages of narrow energy band and high intrinsic conductivity. [18] Meanwhile, the large interlayer spacing (0.65 nm) of WSe 2 is conducive to the rapid transport of sodium ions. Although CoSe 2 and WSe 2 , as newly but rarely studied materials, have been proved to be potentially suitable candidates for SIBs, their insufficiently high ionic and electronic conductivity have still hindered the charge transfer substantially, limiting SIBs battery advancements, especially the rate performance. On that account, various strategies have been proposed to further boost ionic and electronic conductivity of CoSe 2 or WSe 2 based anode materials.As is well known, the combination of active materials and carbonaceous materials, such as the introduction of carbon Heterojunction, with the advantage of fast charge transfer dynamics, is considered to be an effective strategy to address the low capacity and poor rate capability of anode materials for sodium-ion batteries (SIBs). As well, carbonaceous materials, as a crucial additive, can effectively ameliorate the ion/electron conductivity of integrated composites, realizing the fast ion transport and charge transfer. Here, motivated by the enhancement effect of carbon and heterojunction on conductivity, it is propose...

An exquisite branch–leaf shaped metal sulfoselenide composite endowing an ultrastable sodium-storage lifespan over 10 000 cycles

“…It is remarkable that, compared with the other reported CoS 2 or CoSe 2 -based anodes, the CNF@CoSSe@C electrode still exhibits overwhelming advantages in terms of rate performance, especially at a rate over 5.0 A g −1 . 16,45–58 Except for the high capacity and superior rate capability, a qualified electrode should also possess ultrastable cyclic stability at a high rate to ensure long-term Na + -storage and release. Experiencing an ultralong de-/sodiation progress up to 13 000 cycles, the reversible capacity of the CNF@CoSSe@C electrode remains as high as 158.2 mA h g −1 with a decaying capacity rate of only 0.01% for each cycle.…”

The Multicomponent Synergistic Effect of Sandwich Structure Hierarchical Nanofibers for Enhanced Sodium Storage

“…The abundant lattice mismatch and defects formed at heterogeneous interfaces change the reaction kinetics and long-range disorder, further affect the transport behavior of carriers. [21][22][23] The diverse redox potentials and out-of-step electrochemical reactions of different components alleviate volumetric strains during intercalation/extraction processes of Na + . [23] Constructing hierarchical micro/nanostructures as anodes for sodium ion batteries is an important approach for exploiting efficient energy storage devices.…”

Self-assembled monodisperse FeSe2 microflowers as an advanced anode material for sodium ion batteries

“…[19][20][21][22] For example, Zhang et al fabricated CoSe 2 /WSe 2 @C/CN heterostructures as anodes for SIBs, which could achieve a remarkable cyclic stability of 277 mA h g À1 at 0.5 A g À1 aer 200 cycles. 23 Yang's group designed SnSe 2 /FeSe 2 @NC, which could achieve an outstanding rate performance of 345 mA h g À1 at 20 A g À1 as Na storage anodes. 24 Wang's group reported that NiSe 2 @-C@MXene could deliver a remarkable cyclic stability of 327 mA h g À1 aer 4000 cycles at 2 A g À1 .…”