Stabilizing Intermediate Phases via Efficient Entrapment Effects of Layered VS₄/SnS@C Heterostructure for Ultralong Lifespan Potassium‐Ion Batteries

Abstract

Potassium‐ion batteries (PIBs) have appealed increasing attention due to the inexpensive K‐element resources and satisfactory electrochemical properties. Presently, there are still challenges for developing desirable anode materials. Two‐dimensional metal sulfides exhibit high specific capacity as host for PIBs, yet the dissolution and agglomeration of unstable reaction intermediate KxSy (K2S, K2S5) inescapability induces large loss of active ingredients and poor reactions reversibility, leading to inferior lifespan. Herein, polar polysulfide VS4 is introduced into SnS nanosheets with constructing layered VS4/SnS heterostructure anchored in graphene scaffold (VS4/SnS@C). In this framework, VS4 with unsaturated bridging (S2)2– can act as the anchoring sites to stabilize intermediates KxSy with efficient entrapment effects. Moreover, the heterostructure can maintain layered SnS and regulate the distribution of KxSy with high conversion reversibility. The reaction reversibility and intermediate absorptivity are enhanced, as confirmed by in situ X‐ray diffraction analysis and theoretical calculations. Consequently, the VS4/SnS@C electrode exhibits ultra‐long lifespans, which achieves a capacity of 168.4 mAh g–1 at 1 A g–1 after 6000 cycles. This strategy of heterostructure design facilitates the understanding of K‐storage mechanisms and significantly enhances the reaction reversibility, providing a thought to address the challenges in metal sulfide anodes toward the development of high‐performance PIBs.

Iron Selenide‐Based Heterojunction Construction and Defect Engineering for Fast Potassium/Sodium‐Ion Storage

“…The GITT measurements verify that enhanced reaction kinetic has been achieved for the NF 11 S/C electrode, and its featured heterojunction structure is considered to contribute the superior electrochemical properties, in contrast to the case of the FS/C electrode. [29] The EIS measurement (Figure S11c, Supporting Information) also supports excellent reaction kinetics of NF 11 S/C electrode, with a much lower impedance of ≈1700 than ≈7500 Ω of FS/C electrode, and this satisfied feature is comparable to the previously reported results. [46] Furthermore, the D K + value of NF 11 S/C electrode after 50 cycles processed similar evolution with case after 8 cycles, demonstrating that fast ion diffusion and high reversibility of NF 11 S/C electrode.…”

“…As revealed in Figure 5f, the NF 11 S/C S11a, Supporting Information). [29] The reaction resistance of the NF 11 S/C electrode derived from the GITT curves (Figure S11b, Supporting Information) is obviously much lower and stable than that of the FS/C electrode. The GITT measurements verify that enhanced reaction kinetic has been achieved for the NF 11 S/C electrode, and its featured heterojunction structure is considered to contribute the superior electrochemical properties, in contrast to the case of the FS/C electrode.…”

“…[1][2][3][4] By virtue of the migration, achieving improved performance. [5,9,[27][28][29] 4) Defect engineering of the metal compound, such as hetero-atomic doping is a promising strategy to modulate lattice spacing and electronic structure of the anode materials, which enables rich lattice defects and active sites, benefiting for relief of volume effect and high capacity delivery. [6,9,30,31] The typical work is nickel-doped Sb 2 Se 3 nanorods designed by Yu and co-workers recently and superior performances as anode material for PIBs have been achieved.…”

Bi@C Nanospheres with the Unique Petaloid Core–Shell Structure Anchored on Porous Graphene Nanosheets as an Anode for Stable Sodium- and Potassium-Ion Batteries

“…The impedance at 3.0 V almost returned to the initial value, showing the high reversibility of the Bi@C@GR-2 electrode. 70,71 In addition, to confirm the alloying mechanism of Bi and K, we examined the detailed structure of the Bi@C@GR-2 electrode at the fully discharged/charged state through TEM, HRTEM, and EDS elemental mapping images (Figure 8b−i). When discharged to 0.005 V, the Bi@C nanospheres were still composed of multiple nanoparticles (Figure 8b), which indicated the stability of the structure of Bi@C@GR-2.…”

Artificial Heterogeneous Interphase Layer with Boosted Ion Affinity and Diffusion for Na/K‐Metal Batteries

“…[27] As previously reported, heterostructures formed by coupling nanocrystals with different bandgaps can enhance the surface reaction kinetics and promote the charge transfer caused by the electric field inside the heterogeneous interface. [32][33][34][35][36] Moreover, metallic nanoparticles are beneficial for the uniform deposition of alkali metal ions, induce a uniform distribution of charge near the solid-liquid interface, and strengthen the mechanical toughness of the interface. [37,38] Therefore, the development of a heterogeneous interface protective layer involving Na (K) salts and metal nanocrystals with high mechanical toughness, ionic conductivity, and stability for NMAs (PMAs) in carbonate-based electrolytes is urgently required.…”