A high-capacity sulfide cathode material, its preparation method and application, and sodium-ion batteries.

Abstract

The present invention provides a high-capacity sulfide cathode material, a preparation method and application thereof, and a sodium-ion battery, relating to the technical field of electrochemical energy storage. A high-capacity sulfide cathode material provided by the present invention has a chemical composition of Na x MS2; wherein 1 < x < 2; M is Fe and / or Ti; the crystal structure of the high-capacity sulfide cathode material is the Ibam space group. In the present invention, the anion sulfur in this material participates in the electrochemical reaction in the form of (S-S) 2‑ / S 2‑ redox pair, and can release a high capacity; its intrinsic electronic conductivity is high, reaching 10 ‑4 S·cm ‑1 or more, and the reaction kinetics conditions are excellent; at the same time, the special crystal structure of this material, along with the storage and release of sodium ions, makes the reversibility of this structure higher and not prone to collapse. Therefore, the sodium-ion battery prepared from the high-capacity sulfide cathode material provided by the present invention has a high specific capacity and excellent cycle stability.

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