Lead-free 0.5BaZr0.2Ti0.8O3–0.5Ba0.7Ca0.3TiO3 (BZT–BCT) thin films were deposited on Pt(1 1 1)/TiO2/SiO2/Si substrates by pulsed laser deposition. The optimal ferroelectric response with a high saturation polarization Ps ~ 110 µC cm−2, remnant polarization Pr ~ 32.5 µC cm−2 along with a coercive field of 0.18 MV cm−1 was observed from the P–E hysteresis loops under an applied frequency of 1 kHz. A giant recoverable energy-storage density of 93.52 J cm−3 at an applied electric field ~3.47 MV cm−1 was observed. The optimized BZT–BCT thin films exhibited a high dielectric constant with a low dielectric loss at room temperature like their bulk counterpart (high dielectric constant (Ɛ ~ 121 81)) and low dielectric loss (tan δ ~ 0.01–0.03) properties. OPP-PFM images revealed switchable ferroelectric distinct polarization contrasts on the application of a  ±12 V dc voltage on the conductive tip at room temperature. Observed enhanced dielectric, ferroelectric and energy density properties of BZT–BCT thin films are useful for next generation electrical energy storage applications.

Single-crystalline metal germanate nanowires, including SrGe4O9, BaGe4O9, and Zn2GeO4 were successfully grown on carbon textile via a simple low-cost hydrothermal method on a large scale. The as-grown germanate nanowires-carbon textiles were directly used as binder-free anodes for lithium-ion batteries, which exhibited highly reversible capacity in the range of 900-1000 mA h g(-1) at 400 mA g(-1), good cyclability (no obvious capacity decay even after 100 cycles), and excellent rate capability with a capacity of as high as 300 mA h g(-1) even at 5 A g(-1). Such excellent electrochemical performance can be ascribed to the three-dimensional interconnected conductive channels composed of the flexible carbon microfibers, which not only serve as the current collector but also buffer the volume change of the active material upon cycling. Additionally, the one-dimensional nanostructures grown directly on the carbon microfibers also ensure fast charge carrier (e(-) and Li(+)) transport, large surface areas, better permeabilities, and more active sites, which also contributed to the improved electrochemical performance.

Aligned Ca2Ge7O16 nanowire arrays were successfully grown on carbon textiles to form hierarchical 3D structures by using a facile hydrothermal method on a large scale. Typical Ca2Ge7O16 nanowires are single crystals that show preferred growth along the [001] direction. The 3D hierarchical structures were used as binder-free anodes for lithium-ion batteries, which showed the features of highly reversible capacity (900-1100 mA h g(-1) at a current density of 300 mA g(-1)), remarkable cycling stability, even over 100 cycles, and good rate capability, with a capacity of about 500 mA h g(-1) at 3 A g(-1). Furthermore, highly bendable full cells were also fabricated, which showed high flexibility, with little voltage change after bending 600 times, and superior temperature tolerance within the range 4-60 °C, thus demonstrating their promising potential for applications in high-performance lithium-ion batteries.