Cubic MnS-FeS2 Composites Derived from a Prussian Blue Analogue as Anode Materials for Sodium-Ion Batteries with Long-Term Cycle Stability

Cubic N,S codoped carbon coating MnS-FeS₂ composites (MnS-FeS₂@NSC) with a hollow structure were prepared and used as anode materials for sodium-ion batteries. MnS-FeS₂@NSC exhibits excellent cycle performance and high rate capability and delivered a reversible capacity of 501.0 mAh g^-1 after 800 cycles at a current density of 0.1 A g^-1 with a capacity retention of 81%. More importantly, the MnS-FeS₂@NSC anode holds long-term cycle stability; the capacity can remain 134.0 mAh g^-1 after 14 500 cycles at 4 A g^-1. Kinetic analysis demonstrated that Na⁺ storage follows a pseudocapacitive dominating process, which is ascribed to the origin of the outstanding rate performance of the MnS-FeS₂@NSC material. The enhancement of electrochemical performance is attributed to the hollow structure and the N,S codoped carbon coating structure, which can reduce the diffusion distance for sodium ions and electrons, alleviate volume expansion during sodium-ion insertion/extraction, and retain the structural integrity effectively. Furthermore, a two-step sodiation processes with FeS₂ sodiation prior to MnS was demonstrated by X-ray diffraction (XRD), and the electrochemical impedance spectroscopy (EIS) spectra might indicate that the accumulation of the metallic elements in the preconversion reaction can accelerate the transfer of electrons and ions in the further conversion process.

Na3V2(PO4)3: an advanced cathode for sodium-ion batteries

Sodium-ion batteries (SIBs) are considered to be the most promising electrochemical energy storage devices for large-scale grid and electric vehicle applications due to the advantages of resource abundance and cost-effectiveness. The electrochemical performance of SIBs largely relies on the intrinsic chemical properties of the cathodic materials. Among the various cathodes, rhombohedral Na3V2(PO4)3 (NVP), a typical sodium super ionic conductor (NASICON) compound, is very popular owing to its high Na+ mobility and firm structural stability. However, the relatively low electronic conductivity makes the theoretical capacity of NVP cathodes unviable even at low rates, not to mention the high rate of charging/discharging. This is a major drawback of NVPs, limiting their future large-scale applications. Herein, a comprehensive review of the recent progresses made in NVP fabrication has been presented, mainly including the strategies of developing NVP/carbon hybrid materials and elemental doping to improve the electronic conductivity of NVP cathodes and designing 3D porous architectures to enhance Na-ion transportation. Moreover, the application of NVP cathodic materials in Na-ion full batteries is summarized, too. Finally, some remarks are made on the challenges and perspectives for the future development of NVP cathodes.

Metal chelate induced in situ wrapping of Ni3S2 nanoparticles into N, S-codoped carbon networks for highly efficient sodium storage

Metal-dithiooxamide chelate derived Ni₃S₂ nanoparticles wrapped in N, S codoped carbon networks exhibit excellent sodium storage performance.

Facile synthesis of a molybdenum phosphide@carbon nanocomposite as an advanced anode material for sodium-ion batteries

The MoP@C nanocomposite was successfully fabricated via a facile sol–gel approach, which demonstrated excellent electrochemical properties as a sodium-ion battery anode.

Self-assembled Mn-doped MoS2 hollow nanotubes with significantly enhanced sodium storage for high-performance sodium-ion batteries

Mn-Doped MoS₂ hollow nanotubes as an anode exhibit an enhanced fast sodium ion transport capability and superb electrochemical properties in sodium-ion batteries.

Advances and Challenges in Metal Sulfides/Selenides for Next-Generation Rechargeable Sodium-Ion Batteries

Rechargeable sodium-ion batteries (SIBs), as the most promising alternative to commercial lithium-ion batteries, have received tremendous attention during the last decade. Among all the anode materials for SIBs, metal sulfides/selenides (MXs) have shown inspiring results because of their versatile material species and high theoretical capacity. They suffer from large volume expansion, however, which leads to bad cycling performance. Thus, methods such as carbon modification, nanosize design, electrolyte optimization, and cut-off voltage control are used to obtain enhanced performance. Here, recent progress on MXs is summarized in terms of arranging the crystal structure, synthesis methods, electrochemical performance, mechanisms, and kinetics. Challenges are presented and effective ways to solve the problems are proposed, and a perspective for future material design is also given. It is hoped that light is shed on the development of MXs to help finally find applications for next-generation rechargeable batteries.

Architecture design of nitrogen-doped 3D bubble-like porous graphene for high performance sodium ion batteries

The nitrogen-doped 3D bubble-like porous graphene (N-3DPG) is a promising candidate for apllication in sodium ion batteries for large-scale electrochemical energy storage.