In this study, porous carbon nanoflowers (PCF) are synthesized using MIL-101-NH₂ as the precursor, and niobium single atoms (Nb-SAs) are anchored on the PCF via ion adsorption and high-temperature pyrolysis processes (Nb-SA/PCF). Structural characterization and density functional theory (DFT) calculations demonstrate an asymmetric coordination environment of Nb-SA, with three in-plane nitrogen atoms from the graphene and two axially oriented oxygen atoms coordinating each niobium center (NbN₃O₂). This asymmetric NbN₃O₂ enhances charge transfer and increases the dipole moment, thereby significantly improving polarization loss. Consequently, the Nb-SA/PCF-based film exhibits an effective absorption bandwidth of 6.00 GHz at a thickness of 2.0 mm. Moreover, the film demonstrates outstanding mechanical strength, flexibility, thermal insulation, and hydrophobicity, broadening its potential for operational applications in demanding environments.

Solar irradiation can efficiently promote the kinetics of the oxygen evolution reaction (OER) during water splitting, where heterojunction catalysts exhibit excellent photoresponsive properties. However, insights into the origins of photoassisted OER catalysis remain unclear, especially the interfaced promotion under convergent solar irradiation (CSI). Herein, novel allotropic Co_5.47N/CoN heterojunctions were synthesized, and corresponding OER mechanisms under CSI were comprehensively uncovered from physical and chemical aspects using the in situ Raman technique and electrochemical cyclic voltammetry method. Our results provide a unique mechanism where high-energy UV light promotes the Co^3+/4+ conversion process in addition to the ordinary photoelectric effect excitation of the Co²⁺ material. Importantly, visible light under CSI can produce a photothermal effect for Co²⁺ excitation and Co^3+/4+ conversion, which promotes the OER significantly more than the usual photoelectric effect. As a result, Co_5.47N/CoN (containing 28% CoN) obtained 317.9% OER enhancement, which provides a pathway for constructing excellent OER catalysts.

Rechargeable Li–S batteries (LSBs) are emerging as an important alternative to lithium-ion batteries (LIBs), owing to their high energy densities and low cost; yet sluggish redox kinetics of LiPSs results in inferior cycle life. Herein, we prepared multifunctional self-supporting hyphae carbon nanobelt (HCNB) as hosts by carbonization of hyphae balls of Rhizopus, which could increase the S loading of the cathode without sacrificing reaction kinetics. Trace platinum (Pt) nanoparticles were introduced into HCNBs (PtHCNBs) by ion-beam sputtering deposition. Based on the X-ray photoelectron spectroscopy analyses, the introduced trace Pt regulated the local electronic states of heteroatoms in HCNBs. Electrochemical kinetics investigation combined with operando Raman measurements revealed the accelerated reaction mechanics of sulfur species. Benefiting from the synergistic catalytic effect and the unique structures, the as-prepared PtHCNB/MWNCT/S cathodes delivered a stable capacity retention of 77% for 400 cycles at 0.5 C with a sulfur loading of 4.6 mg cm⁻². More importantly, remarkable cycling performance was achieved with an high areal S loading of 7.6 mg cm⁻². This finding offers a new strategy to prolong the cycle life of LSBs.

Among the alternatives to lithium-ion batteries, lithium–sulfur (Li–S) batteries are considered as an attractive option because of their high theoretical energy density of 2570 Wh kg⁻¹. However, the application of the Li–S battery has been plagued by the rapid failure of the Li anode due to the Li dendrite growth and severe parasitic reactions between Li and lithium polysulfides. The physicochemical properties of the solid–electrolyte interphase have a profound impact on the performance of the Li anode. Herein, a lithium polyacrylic acid/lithium nitrate (LPL)-protective layer is developed to inhibit the dendrite Li growth and parasitic reactions by tailoring the spatial distribution and content of LiN_xO_y and Li₃N at the SEI. The modified SEI is thoroughly investigated for compositions, ion transport properties, and Li plating/stripping kinetics. Consequently, the Li–S cell with a high S loading cathode (5.0 mg cm⁻²), LPL layer-protected thin Li anode (50 μm), and 40 μL electrolyte shows a long life span of 120 cycles. This work evokes the avenue for regulating the spatial distribution of inorganic nitride at the SEI to suppress the formation of Li dendrites and parasitic reactions in Li–S batteries and perhaps guiding the design of analogous battery systems.