Encapsulating Sulfides into Tridymite/Carbon Reactors Enables Stable Sodium Ion Conversion/Alloying Anode with High Initial Coulombic Efficiency Over 89%

Abstract

Electrode dissolution/collapses and interfacial reactions pose challenges to batteries, leading to pronounced capacity loss particularly during the initial few cycles. As high‐capacity conversion/alloying anodes for sodium storage, metal sulfides generally show unsatisfactory performances like poor initial Coulombic efficiency (ICE; mostly <70% in the usual electrolyte) and inferior cyclic stability due to thick solid‐electrolyte interface (SEI) layer formation and ubiquitous volume/phase changes. Using SnS2 as an example, here, sulfides are elaborately encapsulated into functionalized amorphous tridymite/carbon reactors to address the above issues. The outer tridymite/carbon manifests good ionic permeability and superb electrochemical/mechanical tolerance against destructive Na+ insertion. Confining actives into tailored reactors endows SnS2 full of nanoboundaries with an ultrahigh ICE of ≈89.13% and remarkable electrochemical attributes including large initial capacity (Max. 733.24 mAh g−1), prominent stability in subsequent cycles, and excellent rate capability. Detailed investigation unveils that thin and steady SEI condition on tridymite/carbon rather than SnS2 is key to achieving outstanding ICE. Engineered reactors always keep intact and free of valence‐state changes, guaranteeing capacities running at a high level without an evident downtrend. Their peculiar functions on enlisting Na+ diffusion/transport and inhibiting sulfides’ release are also discussed. Packed full‐cell Na‐ion batteries with less irreversibility may show great potential in practical utilizations.

A gradient hexagonal-prism Fe3Se4@SiO2@C configuration as a highly reversible sodium conversion anode

“…Nevertheless, the separate lattices of SiO 2 and the PDA-derived carbon layer cannot be accurately distinguished owing to their tight layer-stacking distances and high merge with each other. 35 A typical HRTEM image is exhibited in Fig. 1f, from which the interlayer distance of roughly 0.266 nm can be clearly found, attributed to the characteristic plane (202) of Fe 3 Se 4 .…”

“…31 Among these approaches, constructing a specialized reactor with high mechanical robustness, superior Na + permeability and chemical inertness has been regarded as an executable method. 35 In principle, phase-stable reactors can assure the solid restriction of each active unit in a onefold conned space, so as to release the mechanical strain induced by structural changes and guarantee the structural integrity of the selenide kernels upon fast Na + de-intercalation. A positive effect in the aspect of performance has emerged via normalized connements (e.g.…”

“…36,37 In this regard, tridymite-type SiO 2 is an ideal choice as an attractive surface-defense reactor for tailoring highefficiency iron selenide-based anodes on account of its intrinsic advantages of remarkable mechanical strength and compression features, rich ionic transport channels and excellent electrochemical inertia during de-/sodiation. 35 Despite these captivating advances, the inferior conductivity of SiO 2 reactors restricts further enhancement of battery performance. Functional integration of SiO 2 and highly conductive carbon reactors can synergistically couple the respective advantages of both reactors to offer double protection for the electrode.…”

Water‐Soluble Salt Template‐Assisted Anchor of Hollow FeS2 Nanoparticle Inside 3D Carbon Skeleton to Achieve Fast Potassium‐Ion Storage

“…[ 18,22 ] To address above issue, constructing a hybrid structure with carbon materials has been employed as an efficient strategy to improve the comprehensive performance of electrode materials. [ 14,23,24 ] In general, through careful design of nanostructures, carbon materials are endowed with good electronic conductivity and good elasticity. [ 23,25,26 ] Therefore, anchoring the active material onto the carbon matrix would not only largely enhance the reaction kinetics, but also alleviate structural damage and pulverization of the active material during K‐ions insertion or extraction, offering extra benefits for the cycling stability of the active materials.…”

Bimetallic Copper Tin Sulfide Nanosheet Arrays Encapsulated in Nitrogen-Doped Carbon Shells for Boosted Sodium Storage Performance

“…Meanwhile, the unique lamellar structure of SnS 2 with large interlayer spacing (5.89 Å) makes it quite suitable for the facile insertion/extraction of Na + . However, the inferior intrinsic electrical conductivity, huge volume change, and continuous pulverization of active materials shall result in the rapid capacity decline and poor rate performance. , In addition, most of these reported SnS 2 -based samples were powder. − The preparation of these electrodes inevitably involves the employment of inactive polymeric binders and conductive agents, which greatly impedes the infiltration of electrolyte into the electrodes and also decreases the energy density of the SIBs. , …”