Fine valence regulation of hydrated vanadium oxide as a novel cathode for stable potassium-ion storage.

Layered VO·HO with a large interlayer spacing of 14 Å is hydrothermally synthesized and used as a cathode for potassium-ion batteries. It exhibits a capacity of 110 mA h g with a capacity retention of 99.2% over 700 cycles.

Structural design enabled a hypotoxic NaFeV(PO) cathode with ultra-fast and ultra-long sodium storage.

Among various cathode materials for sodium-ion batteries, NaV(PO) has attracted much attention due to its outstanding electrochemical performance. However, the toxicity and expensive price of vanadium limit its practical application. Therefore, the substitution of vanadium with nontoxic and inexpensive transition metal elements is significant.

Active-Site-Specific Structural Engineering Enabled Ultrahigh Rate Performance of the NaLiFe(PO)(PO) Cathode for Lithium-Ion Batteries.

Iron-based mixed-polyanionic cathode NaFe(PO)(PO) (NFPP) has advantages of environmental benignity, easy synthesis, high theoretical capacity, and remarkable stability. From NFPP, a novel Li-replaced material NaLiFe(PO)(PO) (NLFPP) is synthesized through active Na-site structural engineering by an electrochemical ion exchange approach. The NLFPP cathode can show high reversible capacities of 103.

Hollow-Sphere-Structured NaFe(PO)(PO)/C as a Cathode Material for Sodium-Ion Batteries.

The mixed polyanionic material NaFe(PO)(PO) combines the advantages of NaFePO and NaFePO in capacity, stability, and cost. Herein, we synthesized carbon-coated hollow-sphere-structured NaFe(PO)(PO) powders by a scalable spray drying route. The optimal sample can deliver a high discharge capacity of 107.

Self-Template Synthesis of NaCrO Submicrospheres for Stable Sodium Storage.

Sodium-ion batteries (SIBs) are the appropriate alternatives to lithium-ion batteries (LIBs) for the large-scale energy storage applications because of the abundant resources and wide distribution of sodium on earth. O3-NaCrO is a promising cathode material for SIBs due to its stable structure and low-cost raw materials. In this paper, we design and synthesize a powder consisting of submicrometer-sized O3-NaCrO spheres (s-NaCrO) self-assembled with nanoflakes, which exhibits faster ion migration ability and strong structure robustness.