3D petal-like NiCo₂S₄ nanostructures have been fabricated via a simple, mild and efficient hydrothermal strategy and the growth mechanism of NiCo₂S₄ nano-petals has been investigated.

Co₃O₄ has received ever-growing interest as an electro-active material for supercapacitors due to its high theoretical specific capacitance (3560 F g⁻¹) and simple synthesis process.

The interlayer modification and the intercalation pseudocapacitance have been combined in vanadium oxide electrode for aqueous zinc‐ion batteries. Intercalation pseudocapacitive hydrated vanadium oxide Mn_1.4V₁₀O₂₄·12H₂O with defective crystal structure, interlayer water, and large interlayer distance has been prepared by a spontaneous chemical synthesis method. The inserted Mn²⁺ forms coordination bonds with the oxygen of the host material and strengthens the interaction between the layers, preventing damage to the structure. Combined with the experimental data and DFT calculation, it is found that Mn²⁺ refines the structure stability, adjusts the electronic structure, and improves the conductivity of hydrated vanadium oxide. Also, Mn²⁺ changes the migration path of Zn²⁺, reduces the migration barrier, and improves the rate performance. Therefore, Mn²⁺‐inserted hydrated vanadium oxide electrode delivers a high specific capacity of 456 mAh g⁻¹ at 0.2 A g^–1, 173 mAh g^–1 at 40 A g^–1, and a capacity retention of 80% over 5000 cycles at 10 A g^–1. Furthermore, based on the calculated zinc ion mobility coefficient and Zn(H₂O)_n²⁺ diffusion energy barrier, the possible migration behavior of Zn(H₂O)_n²⁺ in vanadium oxide electrode has also been speculated, which will provide a new reference for understanding the migration behavior of hydrated zinc‐ion.

N,S-Doped activated carbon was directly prepared via a facile and cost-efficient hydrothermal reaction, followed by alkali activation of elm flower (EL)-derived biomass. The EL-derived activated carbon (ELAC) had N and S contents of 2.21 and 6.06 atom %, respectively, in addition to a high Brunauer–Emmett–Teller (BET) surface area of 2048.6 m² g^–1 and moderate pore volume of 0.88 cm³ g^–1. Owing to its high BET surface area and N/S functional groups, ELAC achieved a specific capacitance of 275 F g^–1 at a current density of 1 A g^–1 and retained a capacitance of 216 F g^–1 at 20 A g^–1. In addition, a symmetric supercapacitor based on N,S-self-doped ELAC electrode provided a capacitance of 62 F g^–1 at a current density of 10 A g^–1, with maximum energy and power densities of 16.8 Wh kg^–1 and 600 W kg^–1, respectively. The capacitance retention was also high, at 87.2%, at 4 A g^–1 after 5000 cycles.