[en] Semi-active suspension has been increasing interests for its outstanding performance and high cost effectiveness, and the magnetorheological (MR) damper is a hotspot in these decades. For the MR damper design, here still are some farther challenges, such as, (1) how to cascade the ideal damper characteristic from full vehicle performance, and what is the ideal off-state performance and the controllable ratio; (2) how to fix the MR damper brought additional mass since the MR fluid density is three times than the traditional damper oil’s, and a promising lightweight and effective configuration and its systematical design approaches should be explored. In this article, the novel MR valve controlled damper (MRVD) and its top-down design methodology are proposed via both the configuration design and system syntheses. Results manifest that the developed MRVD prototype matches the target minibus requirement very well with consumption of 3 W drive power and 6.1 ml MR fluids, demonstrating superior dynamic performance, lightweight compact structure, low energy consumption and cost, and a promising application in semi-active suspensions. (paper)

[en] Highlights: • Impedance spectroscopy is employed to study frequency response of porous electrodes. • Potassium hydroxide-activated carbons are used as model systems in supercapacitors. • A simple equivalent circuit is proposed based on the transmission line model. • Frequency-dependant relaxation times, capacitive and resistive elements are evaluated. • Non-ideal capacitive performance of various porous carbon electrodes is investigated. This work considers the relationship between the morphology of porous carbon materials used for supercapacitors and the electrochemical impedance spectroscopy (EIS) response. EIS is a powerful tool that can be used to study the porous 3-dimensional electrode behavior in different electrochemical systems. Porous carbons prepared by treatment of cellulose with different compositions of potassium hydroxide (KOH) were used as model systems to investigate the form vs. electrochemical function relationship. A simple equivalent circuit that represents the electrochemical impedance behavior over a wide range of frequencies was designed. The associated impedances with the bulk electrolyte, Faradaic electrode processes and different pore size ranges were investigated using a truncated version of the standard transmission line model. The analysis considers the requirements of porous materials as electrodes in supercapacitor applications, reasons for their non-ideal performance and the concept of ‘best capacitance’ behavior in different frequency ranges.

[en] The uniformly nanosized NiO were prepared via chemical co-precipitation method. Electrochemical characterization of the NiO nanoparticles showed the initial specific discharge capacity reaches 900 mAh/g at 0.1 A/g and 500 mAh/g at 2 A/g, which reveals that the as-synthesized material could be potential candidate of anode material for LIBS. (paper)

[en] Polypyrrole (PPy) has high electrochemical activity and low cost, so it has great application prospects in wearable supercapacitors. Herein, we have successfully prepared polypyrrole/reduced graphene oxide (PPy/rGO) nanocomposite cotton fabric (NCF) by chemical polymerization, which exhibits splendid electrochemical performance compared with the individual. The addition of rGO can block the deformation of PPy caused by the expansion and contraction. The as-prepared PPy-0.5/rGO NCF electrode exhibits the brilliant specific capacitance (9300 mF cm⁻² at 1 mA cm⁻²) and the capacitance retention with 94.47% after 10 000 cycles. At the same time, the superior capacitance stability under different bending conditions and reuse capability have been achieved. All-solid-state supercapacitor has high energy density of 167 μWh cm⁻² with a power density of 1.20 mW cm⁻². Therefore, the PPy-0.5/rGO NCF electrode has a broad application prospect in high-performance flexible supercapacitor fabric electrode. (paper)

[en] Heteroatom-doped carbon materials with a high specific area, a well-defined porous structure is important to high-performance supercapacitors (SCs). Here, S and N co-doped three-dimensional porous graphene aerogel (NS-3DPGHs) have been synthesized in a facile and efficient self-assembly process with thiourea acting as the reducing and doping agent solution. Operating as a SC electrode, fabricated co-doping graphene, i.e. the sample of NS-3DPGH-150 exhibits the highest specific capacitance of 412.9 F g⁻¹ under 0.5 A g⁻¹ and prominent cycle stabilization with 96.4% capacitance retention in the back of 10 000 cycles. Furthermore, based on NS-3DPGH-150, the symmetrical supercapacitor as-prepared in 6 M KOH displays a superior energy density of 12.9 Wh kg⁻¹ under the power density of 249 W kg⁻¹. Hence, NS-3DPGHs could be considered as an excellent candidate for SCs. (paper)

[en] The electrochemical effect of isotope (EEI) of water is introduced in the Zn-ion batteries (ZIBs) electrolyte to deal with the challenge of severe side reactions and massive gas production. Due to the low diffusion and strong coordination of ions in D${}_2$O, the possibility of side reactions is decreased, resulting in a broader electrochemically stable potential window, less pH change, and less zinc hydroxide sulfate (ZHS) generation during cycling. Moreover, we demonstrate that D${}_2$O eliminates the different ZHS phases generated by the change of bound water during cycling because of the consistently low local ion and molecule concentration, resulting in a stable interface between the electrode and electrolyte. The full cells with D${}_2$O-based electrolyte demonstrated more stable cycling performance which displayed ∼100 % reversible efficiencies after 1,000 cycles with a wide voltage window of 0.8-2.0 V and 3,000 cycles with a normal voltage window of 0.8-1.9 V at a current density of 2 A g${}^{-<!--\; ???\; -->1}$. (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH)

[en] Rechargeable aqueous zinc-iodine batteries (ZIBs) are considered a promising newly-developing energy-storage system, but the corrosion and dendritic growth occurring on the anode seriously hinder their future application. Here, the corrosion mechanism of polyiodide is revealed in detail, showing that it can spontaneously react with zinc and cause rapid battery failure. To address this issue, a sulfonate-rich ion-exchange layer (SC-PSS) is purposely constructed to modulate the transport and reaction chemistry of polyiodide and Zn${}^{2+}$ at the zinc/electrolyte interface. The resulting ZIBs can work properly over 6000 cycles with high-capacity retention (90.2%) and reversibility (99.89%). Theoretical calculations and experimental characterization reveal that the SC-PPS layer blocks polyiodide permeation through electrostatic repulsion, while facilitating desolvation of Zn(H${}_2$O)${}_6$${}^{2+}$ and restricting undesirable 2D diffusion of Zn${}^{2+}$ by chemisorption. (© 2023 Wiley‐VCH GmbH)

[en] With the rapid growth in energy consumption, renewable energy is a promising solution. However, renewable energy (e.g., wind, solar, and tidal) is discontinuous and irregular by nature, which poses new challenges to the new generation of large-scale energy storage devices. Rechargeable batteries using aqueous electrolyte and multivalent ion charge are considered more suitable candidates compared to lithium-ion and lead-acid batteries, owing to their low cost, ease of manufacture, good safety, and environmentally benign characteristics. However, some substantial challenges hinder the development of aqueous rechargeable multivalent ion batteries (AMVIBs), including the narrow stable electrochemical window of water (≈1.23 V), sluggish ion diffusion kinetics, and stability issues of electrode materials. To address these challenges, a range of encouraging strategies has been developed in recent years, in the aspects of electrolyte optimization, material structure engineering and theoretical investigations. To inspire new research directions, this review focuses on the latest advances in cathode materials for aqueous batteries based on the multivalent ions (Zn${}^{2+}$, Mg${}^{2+}$, Ca${}^{2+}$, Al${}^{3+}$), their common challenges, and promising strategies for improvement. In addition, further suggestions for development directions and a comparison of the different AMVIBs are covered. (© 2021 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH)

[en] Vacancy engineering has been proved repeatedly as an adoptable strategy to boost electrocatalysis, while its poor selectivity restricts the usage in nitrogen reduction reaction (NRR) as overwhelming competition from hydrogen evolution reaction (HER). Revealed by density functional theory calculations, the selenium vacancy in ReSe${}_2$ crystal can enhance its electroactivity for both NRR and HER by shifting the d‐band from −4.42 to −4.19 eV. To restrict the HER, we report a novel method by burying selenium vacancy-rich ReSe${}_2$@carbonized bacterial cellulose (V${}_r$-ReSe${}_2$@CBC) nanofibers between two CBC layers, leading to boosted Faradaic efficiency of 42.5 % and ammonia yield of 28.3 μg h${}^{-<!--\; ???\; -->1}$ cm${}^{-<!--\; ???\; -->2}$ at a potential of -0.25 V on an abrupt interface. As demonstrated by the nitrogen bubble adhesive force, superhydrophilic measurements, and COMSOL Multiphysics simulations, the hydrophobic and porous CBC layers can keep the internal V${}_r$-ReSe${}_2$@CBC nanofibers away from water coverage, leaving more unoccupied active sites for the N${}_2$ reduction (especially for the potential determining step of proton-electron coupling and transferring processes as *NN → *NNH). (© 2020 Wiley‐VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] Sodium super-ionic conductor (NASICON)-structured phosphates are emerging as rising stars as cathodes for sodium-ion batteries. However, they usually suffer from a relatively low capacity due to the limited activated redox couples and low intrinsic electronic conductivity. Herein, a reduced graphene oxide supported NASICON Na${}_3$Cr${}_{0.5}$V${}_{1.5}$(PO${}_4$)${}_3$ cathode (VC/C-G) is designed, which displays ultrafast (up to 50 C) and ultrastable (1 000 cycles at 20 C) Na${}^{+}$ storage properties. The VC/C-G can reach a high energy density of ≈470 W h kg${}^{-<!--\; ???\; -->1}$ at 0.2 C with a specific capacity of 176 mAh g${}^{-<!--\; ???\; -->1}$ (equivalent to the theoretical value); this corresponds to a three-electron transfer reaction based on fully activated V${}^{5+}$/V${}^{4+}$, V${}^{4+}$/V${}^{3+}$, V${}^{3+}$/V${}^{2+}$ couples. In situ X-ray diffraction (XRD) results disclose a combination of solid-solution reaction and biphasic reaction mechanisms upon cycling. Density functional theory calculations reveal a narrow forbidden-band gap of 1.41 eV and a low Na${}^{+}$ diffusion energy barrier of 0.194 eV. Furthermore, VC/C-G shows excellent fast-charging performance by only taking ≈11 min to reach 80% state of charge. The work provides a widely applicable strategy for realizing multi-electron cathode design for high-performance SIBs. (© 2022 The Authors. Advanced Energy Materials published by Wiley‐VCH GmbH)