C17H14N2O6S·C3H7NO, triclinic, P1 ‾(no. 2), a = 5.4146(4) Å, b = 11.7925(8) Å, c = 16.9527(12) Å, α = 85.238(2)°, β = 86.674(4)°, γ = 78.959(2)°, V = 1057.77(13) Å3, Z = 2, Rgt (F) = 0.0418, wRref (F 2) = 0.1175, T = 296(2) K.

The energy storage behaviors of MnO2 for aqueous Zn-MnO2 batteries mainly depend on the Zn2+/H+ intercalation but are limited by poor ion/electron migration dynamics and stability. Herein, a strategy is proposed that promoting proton migration kinetics ameliorates H+ storage activity by introducing Ni2+ into γ-MnO2 (Ni-MnO2). Ni2+ can lower the diffusion barrier of H+ and selectively induce the ion intercalation, thereby alleviating the electrostatic interaction with the lattice. Moreover, Ni2+ enables the adjacent [MnO6] octahedrons to have better electron conductivity. The Ni-MnO2 exhibits superior rate performance (nearly four times specific capacity compared with MnO2) and ultra-long-cycle stability (100% of capacity retention after 11 000 cycles at 3.0 A g−1). The calculation indicates that the Ni-MnO2 allows H+ migrate rapidly along the one-dimensional tunnel due to reduction of the activation energy caused by Ni2+ regulating, thus achieving excellent reaction kinetics. This work brings great potential for the development of high-performance aqueous Zn-MnO2 batteries.

Developing highly active and robust oxygen evolution reaction (OER) electrocatalysts is still a critical challenge for water electrolyzers and metal–air batteries. Realizing the dynamic evolution of the intermediate and charge transfer during OER and developing a clear OER mechanism is crucial to design high-performance OER catalysts. Recently in Nature, Xue and colleagues revealed a new OER mechanism, coupled oxygen evolution mechanism (COM), which involves a switchable metal and oxygen redox under light irradiation in nickel oxyhydroxide-based materials. This newly developed mechanism requires a reversible geometric conversion between octahedron (NiO6) and square planar (NiO4) to achieve electronic states with both “metal redox” and “oxygen redox” during OER. The asymmetric structure endows NR-NiOOH with a nonoverlapping region between the dz2 orbitals and a1g* bands, which facilitate the geometric conversion and enact the COM pathway. As a result, NR-NiOOH exhibited better OER activity and stability than the traditional NiOOH.

We have investigated the waveform distortion of energetic particle driven off-axis fishbone mode (OFM) in tokamak plasmas with kinetic magnetohydrodynamic (MHD) hybrid simulations. We extended our previous simulations (Liet al2022Nucl. Fusion62026013) by considering higher- nharmonics in the MHD fluid, wherenis toroidal mode number. The waveform distortion is successfully reproduced in the simulation for both magnetic fluctuations and temperature fluctuations. It is clarified that the waveform distortion arises from the superposition of then  = 2 harmonics on the fundamentaln  = 1 harmonics of OFM, where then  = 2 harmonics are generated by the MHD nonlinearity from then  = 1 OFM. Two types of waveform distortion can occur depending on the phase relationship between then  = 1 andn  = 2 harmonics and the relative amplitude of then  = 2 harmonics to then  = 1 harmonics. Lissajous curve analyses indicate that the wave couplings between then  = 1 andn  = 2 harmonics with phase-lock {sim}piand {sim}0lead to 'rising distortion' and 'falling distortion', respectively. The two types of waveform distortion can be attributed to the strong shearing profile of radial MHD velocity withn  = 2 around theq  = 2 magnetic flux surface. The dependence of waveform distortion on viscosity is investigated. It is found that the viscosity which is needed to reproduce the waveform distortion is larger than that in the experiment.