Electrolyte/Structure-Dependent Cocktail Mediation Enabling High-Rate/Low-Plateau Metal Sulfide Anodes for Sodium Storage

Abstract

As promising anodes for sodium-ion batteries, metal sulfides ubiquitously suffer from low-rate and high-plateau issues, greatly hindering their application in full-cells. Herein, exemplifying carbon nanotubes (CNTs)-stringed metal sulfides superstructure (CSC) assembled by nano-dispersed SnS2 and CoS2 phases, cocktail mediation effect similar to that of high-entropy materials is initially studied in ether-based electrolyte to solve the challenges. The high nano-dispersity of metal sulfides in CSC anode underlies the cocktail-like mediation effect, enabling the circumvention of intrinsic drawbacks of different metal sulfides. By utilizing ether-based electrolyte, the reversibility of metal sulfides is greatly improved, sustaining a long-life effectivity of cocktail-like mediation. As such, CSC effectively overcomes low-rate flaw of SnS2 and high-plateau demerit of CoS2, simultaneously realizes a high rate and a low plateau. In half-cells, CSC delivers an ultrahigh-rate capability of 327.6 mAh g−1anode at 20 A g−1, far outperforming those of monometallic sulfides (SnS2, CoS2) and their mixtures. Compared with CoS2 phase and SnS2/CoS2 mixture, CSC shows remarkably lowered average charge voltage up to ca. 0.62 V. As-assembled CSC//Na1.5VPO4.8F0.7 full-cell shows a good rate capability (0.05 ~ 1.0 A g−1, 120.3 mAh g−1electrode at 0.05 A g−1) and a high average discharge voltage up to 2.57 V, comparable to full-cells with alloy-type anodes. Kinetics analysis verifies that the cocktail-like mediation effect largely boosts the charge transfer and ionic diffusion in CSC, compared with single phase and mixed phases. Further mechanism study reveals that alternative and complementary electrochemical processes between nano-dispersed SnS2 and CoS2 phases are responsible for the lowered charge voltage of CSC. This electrolyte/structure-dependent cocktail-like mediation effect effectively enhances the practicability of metal sulfide anodes, which will boost the development of high-rate/-voltage sodium-ion full batteries.

Molten Salts Etching Route Driven Universal Construction of MXene/Transition Metal Sulfides Heterostructures with Interfacial Electronic Coupling for Superior Sodium Storage

“…The excellent electrochemical performance of Ti 3 C 2 T x /MS y //NVP systems compared with that of other full-cell devices reconfirms the great application prospect of Ti 3 C 2 T x /MS y anode and the generality of the raised strategy (Figure 7f and Table S4, Supporting Information). [5,7,13,25,38,47,57,65,66]…”

Stable Electrochemical Properties of Magnesium-Doped Co-Free Layered P2-Type Na0.67Ni0.33Mn0.67O2 Cathode Material for Sodium Ion Batteries

“…In hexagonal layered materials, the lattice constant a represents the distance between transition metal ions and the lattice constant c represents the distance between transition metal layers. 34 In the octahedron coordination, since the size of Mg 2+ (0.72 Å) is slightly larger than that of Ni 2+ (0.69 Å), the lattice parameters increase after Mg ion replacement. The Rietveld method was used to refine the data, 35 which increased the distance between transition metal ions and transition metal layers, indicating that Mg 2+ entered the transition metal position.…”

“…Supporting Information Table S2 shows information on the Rietveld refined lattice parameters and detailed structures. In hexagonal layered materials, the lattice constant a represents the distance between transition metal ions and the lattice constant c represents the distance between transition metal layers . In the octahedron coordination, since the size of Mg 2+ (0.72 Å) is slightly larger than that of Ni 2+ (0.69 Å), the lattice parameters increase after Mg ion replacement.…”

Pea‐like MoS2@NiS1.03–carbon heterostructured hollow nanofibers for high‐performance sodium storage

“…On the other hand, introduction of intrinsic highly conductive and high theoretical capacity heterogeneous components such as Fe 9 S 10 , Sb 2 S 3 , and NiS 2 can considerably increase the conductivity of MoS 2 and accelerate the reaction kinetics of sodium ions. 26,[44][45][46][47][48][49] For instance, heterostructure Sb 2 S 3 / MoS 2 , 15 MnS-MoS 2 , 25 Bi 2 S 3 /MoS 2 , 44 Ni 3 S 2 @MoS 2 , 50 and SnS-MoS 2 51 have been reported that can deliver high electrochemical performance. Besides metal sulfide composition, low-cost carbonaceous materials have also been comprehensively used to embellish anode materials due to their good electric conductivity, which can improve energy storage properties.…”