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Electronic structure defines the conductivity and ion absorption characteristics of a functional electrode, significantly affecting the charge transfer capability in batteries, while it is rarely thought to be involved in mesoscopic volume and diffusion kinetics of the host lattice for promoting ion storage. Here, we first correlate the evolution in electronic structure of the Mo6S8cathode with the ability to bound volume expansion and accelerate diffusion kinetics for high-performance aqueous Cu2+storage. Operandosynchrotron energy-dispersive X-ray absorption spectroscopy reveals that accumulative delocalized Mo 4d electrons enhance the Mo–Mo interaction with distinctly contracting and uniformizing Mo6clusters during the reduction of Mo6S8, which potently restrain lattice expansion and release space to promote Cu2+diffusion kinetics. Operandosynchrotron X-ray diffraction and comprehensive characterizations further validate the structural and electrochemical properties induced by the Cu2+intercalation electronic structure, endowing the Mo6S8cathode a high specific capacity with small volume expansion, fast ions diffusion, and long-term cycling stability.

Exploring stable and durable cathodes for cost-effective reversible aqueous batteries is highly desirable for grid-scale energy storage applications, but significant challenges remain. Herein, we disclosed an ultrastable Cu2+intercalation chemistry in mass-produced exfoliated NbS2nanosheets to build ultralong lifespan aqueous batteries with cost advantages. Anisotropic interplanar expansion of NbS2lattices balanced dynamic Cu2+incorporation and the highly reversible redox reaction of Nb4+/Nb(4−δ)+couple were illuminated by operando synchrotron X-ray diffraction and energy dispersive X-ray absorption spectroscopy, affording an extraordinary capacity of approximately 317 mAh g–1at 1 A g–1and a good stability of 92.2% capacity retention after 40000 cycles at 10 A g–1. Impressively, a budget NbS2||Fe hybrid ion cell involving an aqueous electrolyte/Fe-metal anode is established and provides a reliable energy supply of 225.4 Wh kg–1at 750 W kg–1, providing insights for building advanced aqueous battery systems for large-scale applications.

Engineering multifunctional superstructure cathodes to conquer the critical issue of sluggish kinetics and large volume changes associated with divalent Zn-ion intercalation reactions is highly desirable for boosting practical Zn-ion battery applications. Herein, it is demonstrated that a MoS2/C19H42N+(CTAB) superstructure can be rationally designed as a stable and high-rate cathode. Incorporation of soft organic CTAB into a rigid MoS2host forming the superlattice structure not only effectively initiates and smooths Zn2+transport paths by significantly expanding the MoS2interlayer spacing (1.0 nm) but also endows structural stability to accommodate Zn2+storage with expansion along the MoS2in-plane, while synchronous shrinkage along the superlattice interlayer achieves volume self-regulation of the whole cathode, as evidenced by in situsynchrotron X-ray diffraction and substantial ex situcharacterizations. Consequently, the optimized superlattice cathode delivers high-rate performance, long-term cycling stability (∼92.8% capacity retention at 10 A g–1after 2100 cycles), and favorable flexibility in a pouch cell. Moreover, a decent areal capacity (0.87 mAh cm–2) is achieved even after a 10-fold increase of loading mass (∼11.5 mg cm–2), which is of great significance for practical applications. This work highlights the design of multifunctional superlattice electrodes for high-performance aqueous batteries.

Protons can penetrate through single-layer graphene, but thicker graphene layers (more than 2 layers), which possess more compact electron density, are thought to be unfavorable for penetration by protons at room temperature and elevated temperatures. In this work, we developed an in situsubsecond time-resolved grazing-incidence X-ray diffraction technique, which fully realizes the real-time observation of the thermal proton interaction with the graphene layers at high temperature. By following the evolution of interlayer structure during the protonation process, we demonstrated that thermal protons can transport through multilayer graphene (more than 8 layers) on nickel foil at 900 °C. In comparison, under the same conditions, the multilayer graphenes are impermeable to argon, nitrogen, helium, and their derived ions. Complementary in situtransport measurements simultaneously verify the penetration phenomenon at high temperature. Moreover, the direct transport of protons through graphene is regarded as the dominant contribution to the penetration phenomenon. The thermal activation, weak interlayer interaction between layers, and the affinity of the nickel catalyst may all contribute to the proton transport. We believe that this method could become one of the established approaches for the characterization of the ions intercalated with 2D materials in situand in real-time.

Electrocatalytic N2oxidation (NOR) into nitrate is a potential alternative to the emerging electrochemical N2reduction (NRR) into ammonia to achieve a higher efficiency and selectivity of artificial N2fixation, as O2from the competing oxygen evolution reaction (OER) potentially favors the oxygenation of NOR, which is different from the parasitic hydrogen evolution reaction (HER) for NRR. Here, we develop an atomically dispersed Fe-based catalyst on N-doped carbon nanosheets (AD-Fe NS) which exhibits an exceptional catalytic NOR capability with a record-high nitrate yield of 6.12 μ mol mg–1h–1(2.45 μ mol cm–2h–1) and Faraday efficiency of 35.63%, outperforming all reported NOR catalysts and most well-developed NRR catalysts. The isotopic labeling NOR test validates the N source of the resultant nitrate from the N2electro-oxidation catalyzed by AD-Fe NS. Experimental and theoretical investigations identify Fe atoms in AD-Fe NS as active centers for NOR, which can effectively capture N2molecules and elongate the N≡N bond by the hybridization between Fe 3d orbitals and N 2p orbitals. This hybridization activates N2molecules and triggers the subsequent NOR. In addition, a NOR-related pathway has been proposed that reveals the positive effect of O2derived from the parasitic OER on the NO3–formation.