Xiaobing Wang

Transition metal chalcogenides have been considered as one kind of the most potential candidate catalysts for oxygen evolution reaction (OER). However, the inevitable sulfur loss during reconstruction process destructs the chemical and electronic structure of catalysts. Herein, we proposed directional metal element migration to fix sulfur on near‐surface region, and evaluated the effect of lattice oxygen compensation on the stability of surface sulfur. Besides, an ‘etching‐compensation factor’ of lattice oxygen is defined as a descriptor on the OER stability with coupled O─O as the key intermediates. It is found that the migration of Fe and S in opposite directions enables high voltage‐dependent reversibility of Ni─O─Fe units during OER for self‐healing of electrode. The further produced full gradient NiFe‐sulfide electrode can stably work for more than 50 000 CV cycles at the scan rate of 50 mV s ⁻¹ , and 800 h of chronopotentiometric at current density of 100 mA cm ⁻² .

Dendrite growth and interfacial side reactions severely impair the stability of lithium negative electrodes. A deeper understanding of the structure-performance relationship between current collectors (CCs) and lithium deposition is crucial for addressing these challenges. In this study, a "random-to-aligned hierarchical porous carbon nanofibers" (r/a-HPCNFs) CC strategy was proposed to realize uniform bottom-up lithium-ion (Li⁺) deposition by analyzing the ion transport within aligned CNF channels. By constructing a top-random/bottom-aligned interface with different charge centers, the dielectric constant can be effectively adjusted, thereby promoting a polarization transformation of the intrinsic electric field and strengthening the driving force for Li⁺ migration toward the bottom of the CC. The symmetric cell assembled with Li-predeposited r/a-HPCNFs operates stably for over 6500 h at 5 mA cm^-2. With less Li predeposition (∼3 mAh, N/P = 2), r/a-HPCNF-based full cells (LiFePO₄, LiNi_0.8Co_0.1Mn_0.1O₂, and sulfur) deliver >80% capacity over 400, 260, and 200 cycles at 3, 2, and 0.5 C, respectively. These results highlight the key role of the random-aligned hierarchical architecture in intrinsic field regulation, enabling dendrite suppression and stable cycling.

Inhibiting dendrite growth is considered one of the most crucial tasks for developing high‐energy‐density lithium metal batteries (LMBs), but it is constrained by the unsteady evolution of the electric‐double‐layer (Li‐EDL) at lithium/electrolyte interface. Herein, the dependence of Li‐EDL evolution on the solvation structure is elucidated based on the changes of solid electrolyte interphase (SEI) and electrostatic shielding effect (ESE) in various salt‐anion systems with/ without K ⁺ added. It is found that the interaction between anions and cations presents competing effect on SEI or ESE formation, in which medium/high donor number (DN) anion would promote its participation in SEI formation, but the dissociation of K ⁺ into Li‐EDL for ESE exhibits a high voltage dependence, resulting in the poor stability of Li‐EDL. Through using PF ₆ ^‒ (low DN value) to release K ⁺ confined by FSI ^‒ (medium DN value), a novel designed LiPF ₆ ‐LiFSI‐K ⁺ ester‐based electrolyte realizes an optimized Li‐EDL with the ability of high quality SEI formation and stable ESE, effectively inhibiting the lithium dendrite formation. The new findings in this study provide an innovative insight on the optimization strategy toward alkali metal anodes community.

The interfacial electric field (IEF) between heterogeneous units plays an important role in the electronic modulation of active centers during oxygen evolution reaction (OER). However, the weak electronic coupling between spatially separated IEFs limits the deep activation of metal sites on the surface of the catalyst. Herein, a proof‐of‐concept strategy is provided that imbed MS₂ (M = Ni₃Fe) species with high spin Fe orbits into heterogeneous units to promote the electron penetrating between IEFs. By designing a Fe₂O₃@MS/MS₂@MO_y model catalyst, the electronic interaction between adjacent IEFs is effectively enhanced for the deep oxidation of bimetals on the surface, breaking the competing relationship between adsorbed evolution mechanism (AEM) and lattice oxygen mechanism (LOM) of catalysts during OER. As a result, the onset overpotential of the synthesized electrode is only 171 mV, and it maintains excellent stability for more than 2300 h at a current density of 10 mA cm⁻² in 1 M KOH + 0.5 M NaCl electrolyte.

Ion-selective membrane has broad application in various fields, while the present solution-processed techniques can only prepare uniform membrane with microscale thickness. Herein, a high-quality polymer membrane with nanoscale thickness and uniformity is precisely prepared by controlling solution spreading and solvent evaporation stability/rate. With the arrayed capillaries, the stable spreading of polymer solution with volume of microliter induces the formation of solution film with micrometers thickness. Moreover, the fast increase of solution dynamic viscosity during solvent evaporation inhibits nonuniform Marangoni flow and capillary flow in solution film. Consequently, the uniform Nafion-Li membranes with ∼200 nm thickness are prepared, while their Li⁺ conductivity is 2 orders of magnitude higher than that of commercially Nafion-117 membrane. Taking lithium-sulfur battery as a model device, the cells (capacities of 8-10 mAh cm^-2) can stably operate for 150 cycles at a S loading of 12 mg cm^-2 and an electrolyte/sulfur ratio of ∼7.