A flexible ferroelectric memory element based on oxide heteroepitaxy has been demonstrated with superior performance.

Uniform yolk–shell V₂O₅ microspheres were synthesized via a facile template-free solvothermal route and subsequent calcination treatment in air. The resulting cathode materials showed a high specific capacity of 220 mA h g⁻¹ after 30 cycles and good rate capability.

Hf0.5Zr0.5O2 (HZO) based ferroelectric-field-effect transistor (FeFET) with a ZrO2seed layer was demonstrated. It was found that the ZrO2seed layer could effectively improve ferroelectric properties of the HZO thin film. The remanent polarization and the coercive voltage of the metal-ferroelectric-insulator-semiconductor (MFIS) structure with the ZrO2-seed layer were larger than those without the seed layer. Moreover, the FeFET with the ZrO2seed layer showed wider counter-clockwise hysteresis loops in the transfer characteristics than that without the seed layer, achieving a large memory window of about 2.8 V. These results validate the advantages of the ZrO2 seed layer in promotion of FeFET performance and thus warrant further study.

In this work, we report a mild and cost-effective solution method to directly grow Ni-substituted Co₃O₄ (ternary NiCo₂O₄) nanorod arrays on Cu substrates. Electrochemical impedance spectroscopy (EIS) measurements show that the values of the electrolyte resistance R_e and charge-transfer resistance R_ct of NiCo₂O₄ are 6.8 and 63.5 Ω, respectively, which are significantly lower than those of binary Co₃O₄ (10.4 and 122.4 Ω). This EIS characterization strongly confirms that the ternary NiCo₂O₄ anode has much higher electrical conductivity than that of the binary Co₃O₄ electrode materials, which should greatly enhance the lithium storage performances. Due to the well-aligned 1D nanorod microstructure and a higher electrical conductivity, these ternary NiCo₂O₄ nanorod arrays manifest high specific capacity, excellent cycling stability (a high reversible capacity of about 830 mA h g⁻¹ was achieved after 30 cycles at 0.5 C) and high rate capability (787, 695, 512, 254, 127 mA h g⁻¹ at 1 C, 2 C, 6 C 50 C and 110 C, respectively).

Silicon nanostructures have been employed as the anodes of lithium-ion batteries to mitigate mechanical and chemical degradation. Conditions for averting fracture have been identified in terms of the Si critical size and its state of charge. Strong size dependencies were observed, and the critical sizes of fracture for different shapes of Si have been found to be: ∼90 nm for nanoparticles, ∼70 nm for nanowires, and ∼33 nm for nanofilms, below which the silicon nanostructures remain undamaged upon lithiation.

Mesoporous interconnected carbon-encapsulated Fe₃O₄ (Fe₃O₄@C) nanospheres assembled from tiny nanoparticle subunits have been synthesized by a one-pot solvothermal decomposition route followed by thermal annealing. Electrochemical characterization of these interconnected Fe₃O₄@C nanospheres exhibits a capacity of 636 mA h g⁻¹ at 0.2–1 C over 50 cycles when employed as anode materials in Li-ion batteries.