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Emerging flexible and wearable electronic products are placing a compelling demand on lightweight transparent energy storage devices. Owing to their distinguishing features of safety, high specific energy, cycling stability, and rapid charge/discharge advantages, Zn‐ion hybrid supercapacitors are a current topic of discussion. However, the trade‐off for optical transmittance and energy density remains a great challenge. Here, a high‐performance Zn‐ion hybrid supercapacitor based on the customizable ultrathin (5 µm), ultralight (0.45 mg cm−2), and ultra‐transparent (87.6%) Ni micromesh based cathode and Zn micromesh anode with the highest figure of merit (84 843) is proposed. The developed flexible transparent Zn‐ion hybrid supercapacitors reveal excellent cycle stability (no decline after 20 000 cycles), high areal energy density (31.69 µWh cm−2), and high power density (512 µW cm−2). In addition, the assembled solid flexible and transparent Zn‐ion hybrid supercapacitor with polyacrylamide gel electrolyte shows extraordinary mechanical properties even under extreme bending and twisting operation. Furthermore, the full device displays a high optical transmittance over 55.04% and can be conformally integrated with diverse devices as a flexible transparent power supply. The fabrication technology offers seamless compatibility with industrial manufacturing, making it an ideal model for the advancement of portable and wearable devices. [ABSTRACT FROM AUTHOR]

Lithium metal batteries are emerging as the next generation of high-density electrochemical energy storage systems because of the ultra-high specific capacity and ultra-low electrochemical potential of the Li metal anode. However, the uneven Li deposition on commercial Cu current collectors result in low Coulombic efficiencies (CEs) and poor cycle life. In this research, we proposed the modification of ZnFx(OH)y on Cu foils to expand the lifespan. As-generated ZnLi alloy and LiF could promote uniform Li nucleation and deposition, thus resulting in an improved Li plating/stripping CE and extended cycle life. The Li-S battery with sulfurized polyacrylonitrile cathode and Li-ZnFx(OH)y@Cu anode (N/P ratio of 1.5:1) maintains 95% capacity after 60 cycles, proving the feasibility of ZnFx(OH)y@Cu for practical applications. [ABSTRACT FROM AUTHOR]

Bi2Mg2/3Nb4/3O7 (BMN) thin films are prepared on Pt–Si substrates by magnetron sputtering, the influence of oxygen on dielectric and energy storage properties of BMN thin films is systematically studied. Under the optimal oxygen argon ratio, the BMN thin films show an acceptable dielectric constant of 161 and low loss of 0.0032. With the increase in oxygen argon ratio, the dielectric loss decreases and the breakdown strength increases. A large recoverable energy density of 61.7 J/cm3 with a high efficiency of 74.6% is obtained for the BMN thin films prepared at oxygen-argon ratio of 1/2. Especially, the BMN thin films exhibit an excellent thermal stability in an ultrawide temperature range from − 100 to 200 °C and strong fatigue endurance during the 1 × 106 charge–discharge cycles. These results suggest that the BMN thin films are a promising candidate for lead-free energy storage application in equipment operation under adverse environments. [ABSTRACT FROM AUTHOR]

Bismuth magnesian niobium (Bi 2 Mg 2/3 Nb 4/3 O 7 , BMNO) thin films are deposited on Pt/Ti/SiO 2 /Si substrates at different substrate temperatures by magnetron sputtering. The effect of substrate temperature on the energy storage properties of BMNO thin films is investigated systematically. The X-ray diffraction pattern reveals the thin films are polycrystalline with cubic pyrochlore structure. The dielectric constant of BMNO thin films increases with the substrate temperature, reaches the maximum value of 161 at 700 °C and starts decreasing thereafter. The maximum electrical breakdown strength and recoverable stored energy density are respectively obtained as 3.78 MV/cm and 58.9 J/cm3 when the BMNO thin films are deposited at 700 °C. In addition, the BMNO thin films possess excellent thermal stability of stored energy properties in a wide range of temperatures (-150 °C–200 °C). These results suggest that the BMNO thin films are a promising candidate for lead-free energy storage application in equipment operation under adverse environments. [ABSTRACT FROM AUTHOR]

Capacitor with high energy density, wide operating temperature range, large power density and environmental friendliness is strongly demanded in modern electrical and electronic devices. In this work, Bi 2 Zn 2/3 Nb 4/3 O 7 (BZN) thin film as a novel lead-free material with ultra-high energy storage density and ultra-wide operating temperature range, is prepared by magnetron sputtering. Dielectric properties and electric breakdown strength depend on the substrate temperature, resulting in the change of energy storage performance. The dielectric constant and breakdown strength reach respectively 182 and 3.81 MV/cm for the BZN thin film prepared at 700 °C, while the maximum recoverable energy storage density (63.5 J/cm3) at 100 Hz is achieved. Moreover, the BZN thin films possess excellent thermal stability of energy storage properties in an ultra-wide temperature range (-150- 250 °C) and strong fatigue endurance after 1 × 106 charge–discharge cycles. These results reveal that the BZN thin film can be a promising candidate for lead-free energy storage application in equipment working in harsh environment. • The BZN films show an ultrahigh energy storage density of 63.5 J/cm3. • The BZN films exhibit excellent performance stability in -150- 250 °C. • The BZN films show strong fatigue endurance after 1 × 106 charge–discharge cycles. • BZN films have a high power density (53.92 MW/cm3). [ABSTRACT FROM AUTHOR]

Supercapacitors with high energy density and long serving life is highly desirable for solving the energy crisis. Herein, we propose a simple strategy to fabricate hollow cobalt metal-organic framework dodecahedron heterostructures composed of Co(CO 3) 0.5 OH·0.11H 2 O [Co-CH], NiCo 2 S 4 and Co 9 S 8 with controllable energy storage kinetics. The decoration of NiCo 2 S 4 nanosheets provides a 6.1-fold higher specific capacity (1011.0 C g−1 at 1 A g−1) than Co 9 S 8. The electrochemical kinetic analysis reveals that the OH- dissociation process plays a decisive role in the structural stability. Surface-loaded pseudo-capacitive materials can promote the reversibility of Faraday redox reaction and OH- diffusion coefficient. Controlled growth of Co-CH nano-needles reduces the diffusion-dominated process and improve the cycling stability by a factor of 4.0–5.8 due to the increased reaction reversibility, charge transfer and OH- diffusion. The two-electrode asymmetric device displays a high energy density of 47.6 W h kg−1 at a power density of 800 W kg−1 and good cycling stability (78.1 % retention after 5000 cycles at 5 A g−1). This work offers an effective approach for fabricating low-cost transition metal complexes that hold great promise for practical energy storage applications. • Hierarchical Co-MOF hollow complexes composed of Co-CH, NiCo 2 S 4 and Co 9 S 8 are designed. • The decoration of NiCo 2 S 4 nanosheets delivers high specific capacity of 1011.0 C g−1. • The OH- dissociation process is found to be more detrimental to the electrode stability. • Growth of Co-CH nano-needles boosts the cycle stability by 5.8 times. • The ASC delivers an energy density of 47.6 Wh/kg at power density of 800 W kg−1. [ABSTRACT FROM AUTHOR]

To obtain high energy density supercapacitors (SCs) to meet the larger demand for electric vehicles and portable electronic products, increasing the mass loading of electrode materials without sacrificing electron and ion conductivity is an ideal avenue. Herein, stable α-phase NiCoAl hydroxides with an expanded interlayer spacing and superior electronic conductivity are efficiently synthesized via the coprecipitation method. Furthermore, the interface is ingeniously regulated by adjusting the proper concentration of the electrolyte to modulate the charge storage form of the electrode to resolve the structure collapse and block ion penetration/diffusion. As expected, the obtained NiCoAl-10 supercapacitor electrode under an ultrahigh mass loading (20.24 mg cm−2) has an ultrahigh area-specific capacitance of 23.85 F cm−2 at 10 mA cm−2, an excellent rate capability of 19.27 F cm−2, even at 40 mA cm−2, and an outstanding long-term cycling stability (87.5% capacity retention after 10,000 cycles). Ultimately, an asymmetric supercapacitor (ASC) device of NiCoAl-10//active carbon (AC) also exhibits a high energy density of 3.29 mWh cm−2 at 18.00 mW cm−2 and remarkable capacity retention. This work further interprets the energy storage mechanism of NiCoAl hydroxides under high mass-loading, and opens a new avenue for meeting the commercial application of high energy density SCs. [Display omitted] • Al-substituted NiCo layered double hydroxides electrodes are constructed. • The Ni 0.75 Co 0.15 Al 0.1 (OH) 2 electrode possesses an ultrahigh mass loading. • The Ni 0.75 Co 0.15 Al 0.1 (OH) 2 electrode exhibits outstanding performances. • This work opens a new avenue for meeting the commercial application of SCs. [ABSTRACT FROM AUTHOR]

• An N-doped graphite layer was first as a coating layer of SnO 2. • Graphene coating can provide conductive network and alleviate volume expansion. • Nitrogen doping can provide active centers and improve interface stability. • SnO 2 @NG displays the outstanding electrochemical performances. Tin dioxide (SnO 2) with multiple electron transport is considered as a potential substitute for graphite due to these advantages of natural abundance, environmental friendliness, and high theoretical capacity. However, the ineluctable volume change and structural crushing limit its practical application. Hence, SnO 2 is coated by an N-doped graphite layer to form the flexible composite anode (SnO 2 @NG), which can provide a conductive network, increase the electronic conductivity, and effectively mitigate the irreversible volume expansion/contraction during the circulation process. Furthermore, the SnO 2 @NG anode shows a high specific capacity and stable cycle performance in lithium-ion batteries (677.7 mAh g−1 after 100 cycles) and sodium-ion batteries (169.7 mAh g−1 after 100 cycles). This excellent electrochemical performance illustrates that SnO 2 @NG has broad application prospects for high-performance energy storage systems. [ABSTRACT FROM AUTHOR]