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Manganese-based Prussian blue analogue (Mn-HCF) has outstanding advantages such as a high discharge platform, high discharge capacity and high energy density compared with other PB and PBAs, which is a very valuable cathode material for sodium-ion batteries. However, the rapid decrease in capacity in the cycle process by the Jahn–Teller effect caused by ${\text{Mn}}^{3+}$ is the main obstacle to the commercialization of Mn-HCF. In this work, Mn/La-HCF @ Fe-HCF was synthesized by doping La element into the Mn-HCF phase to suppress the Jahn–Teller effect of Mn ions and coating the Fe-HCF phase outside to protect the Mn-HCF phase from electrolyte corrosion. Benefiting from the inhibition of the Jahn–Teller effect of ${\text{Mn}}^{3+}$ by the abundant electronic energy level structure of La element and the protection of Fe-HCF phase relative to Mn-HCF phase, the initial discharge capacity of Mn/La-HCF @ Fe-HCF can reach 135.6 mAh ${\text{g}}^{-1}$ at current density of 0.1 C, and it still has a high discharge capacity of 112.2mAh ${\text{g}}^{-1}$ at current density of 5 C. After 300 cycles at a current density of 2 C, the reversible capacity of 117.6mAh ${\text{g}}^{-1}$ is maintained (capacity retention rate is 86.1%). The results show that this method of internal doping and outsourcing can greatly improve the electrochemical performance of Mn-HCF, and provide feasible ideas for the commercialization of Mn-HCF.

A series of (Pb_0.4Sr_0.6)_1-xLa_2x/3TiO₃ (PSLT) thin films were deposited on ITO/glass substrates by sol–gel technique. Their phase status, surface morphology, and dielectric properties were studied by X-ray diffraction, scanning electron microscope, and impedance analyzer, respectively. Results show that the PSLT thin films were consisted of tetragonal perovskite phase PSLT thin films for x < 0.4, and cubic perovskite phase PSLT thin films for x > 0.4. Dielectric properties such as dielectric constants, dielectric tunabilitis, and inharmonic coefficient were characterized as a function of the film composition.