No abstract

Hierarchical hollow NiCo2S4 microspheres with a tunable interior architecture are synthesized by a facile and cost‐effective hydrothermal method, and used as a cathode material. A three‐dimensional (3D) porous reduced graphene oxide/Fe2O3 composite (rGO/Fe2O3) with precisely controlled particle size and morphology is successfully prepared through a scalable facile approach, with well‐dispersed Fe2O3 nanoparticles decorating the surface of rGO sheets. The fixed Fe2O3 nanoparticles in graphene efficiently prevent the intermediates during the redox reaction from dissolving into the electrolyte, resulting in long cycle life. KOH activation of the rGO/Fe2O3 composite is conducted for the preparation of an activated carbon material–based hybrid to transform into a 3D porous carbon material–based hybrid. An energy storage device consisting of hollow NiCo2S4 microspheres as the positive electrode, the 3D porous rGO/Fe2O3 composite as the negative electrode, and KOH solution as the electrolyte with a maximum energy density of 61.7 W h kg−1 is achieved owing to its wide operating voltage range of 0–1.75 V and the designed 3D structure. Moreover, the device exhibits a high power density of 22 kW kg−1 and a long cycle life with 90% retention after 1000 cycles at the current density of 1 A g−1.

In this study, we report the fabrication of a flexible film shaped resistive-type pressure sensor with high performance and versatile applications.

Lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) have received much attention in energy storage system. In particular, among the great efforts on enhancing the performance of LIBs and SIBs, yolk–shell (YS) structured materials have emerged as a promising strategy toward improving lithium and sodium storage. YS structures possess unique interior void space, large surface area and short diffusion distance, which can solve the problems of volume expansion and aggregation of anode materials, thus enhancing the performance of LIBs and SIBs. In this review, we present a brief overview of recent advances in the novel YS structures of spheres, polyhedrons and rods with controllable morphology and compositions. Enhanced electrochemical performance of LIBs and SIBs based on these novel YS structured anode materials was discussed in detail.

Wire‐supercapacitors have drawn extensive attentions as a promising candidate for future wearable electronic devices. However, the relative lower energy densities and imperfect physical properties (e.g., length, tenacity, flexibility, and stability) seriously hinder their real applications as energy storage devices in wearable electronics. Herein, the fabrication of wire‐supercapacitors is reported with the length of longer than 1 m, based on CoNiO2‐nanowires@carbon‐fibers electrodes with a high capacity of 1.68 mF cm−1 and a high energy density of 0.95 mWh cm−3, respectively. The device shows no obvious performance degradation when suffering cycling, bending, pulling, tying, and weaving. After weaving as Chinese knot, watchband, belt, and clothes textile, the wire‐supercapacitors work well as the wearable energy‐storage units to power the personal electronics.

The rechargeable aluminum-ion battery (AIB) is a promising candidate for next-generation high-performance batteries, but its cathode materials require more development to improve their capacity and cycling life. We have demonstrated the growth of MoSe 2 three-dimensional helical nanorod arrays on a polyimide substrate by the deposition of Mo helical nanorod arrays followed by a low-temperature plasma-assisted selenization process to form novel cathodes for AIBs. The binder-free 3D MoSe 2 -based AIB shows a high specific capacity of 753 mAh g −1 at a current density of 0.3 A g −1 and can maintain a high specific capacity of 138 mAh g −1 at a current density of 5 A g −1 with 10 000 cycles. Ex situ Raman, XPS, and TEM characterization results of the electrodes under different states confirm the reversible alloying conversion and intercalation hybrid mechanism during the discharge and charge cycles. All possible chemical reactions were proposed by the electrochemical curves and characterization. Further exploratory works on interdigital flexible AIBs and stretchable AIBs were demonstrated, exhibiting a steady output capacity under different bending and stretching states. This method provides a controllable strategy for selenide nanostructure-based AIBs for use in future applications of energy-storage devices in flexible and wearable electronics.

Effectively composite materials with optimized structures exhibited promising potential in continuing improving the electrochemical performances of supercapacitors in the past few years. Here, we proposed a rational design of branched CoMoO4@CoNiO2 core/shell nanowire arrays on Ni foam by two steps of hydrothermal processing. Owing to the high activity of the scaffold-like CoMoO4 nanowires and the well-defined CoNiO2 nanoneedles, the three-dimensional (3D) electrode architectures achieved remarkable electrochemical performances with high areal specific capacitance (5.31 F/cm(2) at 5 mA/cm(2)) and superior cycling stability(159% of the original specific capacitance, i.e., 95.7% of the maximum retained after 5000 cycles at 30 mA/cm(2)). The all-solid-state asymmetric supercapacitors composed of such electrode and activated carbon (AC) exhibited an areal specific capacitance of 1.54 F/cm(2) at 10 mA/cm(2) and a rate capability (59.75 Wh/kg at a 1464 W/kg) comparable with Li-ion batteries. It also showed an excellent cycling stability with no capacitance attenuation after 50000 cycles at 100 mA/cm(2). After rapid charging (1 s), such supercapacitors in series could lighten a red LED for a long time and drive a mini motor effectively, demonstrating advances in energy storage, scalable integrated applications, and promising commercial potential.

Aluminum–sulfur batteries (ASBs) have attracted substantial interest due to their high theoretical specific energy density, low cost, and environmental friendliness, while the traditional sulfur cathode and ionic liquid have very fast capacity decay, limiting cycling performance because of the sluggishly electrochemical reaction and side reactions with the electrolyte. Herein, we demonstrate, for the first time, excellent rechargeable aluminum–selenium batteries (ASeBs) using a new deep eutectic solvent, thiourea-AlCl3, as an electrolyte and Se nanowires grown directly on a flexible carbon cloth substrate (Se NWs@CC) by a low-temperature selenization process as a cathode. Selenium (Se) is a chemical analogue of sulfur with higher electronic conductivity and lower ionization potential that can improve the battery kinetics on the sluggishly electrochemical reaction and the reduction of the polarization where the thiourea-AlCl3 electrolyte can stabilize the side reaction during the reversible conversion reaction of Al–Se alloying processes during the charge–discharge process, yielding a high specific capacity of 260 mAh g–1 at 50 mA g–1 and a long cycling life of 100 times with a high Coulombic efficiency of nearly 93% at 100 mA g–1. The working mechanism based on the reversible conversion reaction of the Al–Se alloying processes, confirmed by the ex situ Raman, XRD, and XPS measurements, was proposed. This work provides new insights into the development of rechargeable aluminum–chalcogenide (S, Se, and Te) batteries.