Yongjie Zhao

Lithium manganese iron phosphate (LiMn _x Fe _{1‐ x} PO ₄ , LMFP) offers higher energy density than LiFePO ₄ but suffers from sluggish kinetics and unfavorable cycling stability caused by Fe/Mn segregation and severe Jahn‐Teller distortion of Mn ³⁺ . Herein, a precursor‐engineered strategy is proposed using a homogeneous spinel FeMn ₂ O ₄ precursor synthesized via solution combustion. Molecular‐level chelation and rapid combustion pre‐lock Fe and Mn cations into a uniform solid‐solution framework, enabling the formation of LiMn _0.67 Fe _0.33 PO ₄ with highly homogeneous cation distribution and reduced lattice distortion. As a result, the LMFP cathode exhibits markedly reduced polarization (38 mV and 101 mV for Fe and Mn plateaus), enhanced Li ⁺ diffusion coefficients (up to 6.75 × 10 ⁻¹² cm ² s ⁻¹ ), and excellent rate capability, delivering ∼76 mAh g ⁻¹ at 10 C. Superior cycling stability is achieved with 89.2% capacity retention after 1000 cycles at 5 C. This work demonstrates precursor‐level cation organization as an effective route to overcoming the kinetic and stability bottlenecks of manganese‐based olivine cathodes.

To address the growing industrial demand for sodium‐ion batteries (SIBs) with high energy density, this work designed and synthesized a novel manganese‐based NASICON‐structure Na ₃ MnTi _0.5 Sn _0.5 (PO ₄ ) ₃ (NMTSP). Leveraging the multi‐step reversible redox reactions of Mn ²⁺ /Mn ³⁺ /Mn ⁴⁺ and Ti ³⁺ /Ti ⁴⁺ , NMTSP exhibits favorable cathodic performance, delivering a reversible specific capacity of 137.4 mAh g ⁻¹ along with favorable cycling stability. When evaluated as an anode, the Sn‐rich NMTSP also shows considerable sodium‐storage capability, with a reversible capacity of 219.0 mAh g ⁻¹ and a retained capacity of 99.4 mAh g ⁻¹ at 571 mA g ⁻¹ . On this basis, an NMTSP||NMTSP symmetric full‐cell was further constructed by taking advantage of the complementary redox characteristics of Mn, Ti, and Sn. The assembled cell delivers an operating voltage of 1.48 V and an energy density of 134.5 Wh kg ⁻¹ , while retaining 76.0% of its capacity after 100 cycles at 315 mA g ⁻¹ . These results demonstrate that Ti/Sn co‐substitution is an effective strategy for tuning the electrochemical behavior of Mn‐based NASICON electrodes and highlight the potential of NMTSP for application in high‐performance symmetric SIBs.

The fabrication of efficient, low‐cost, and stable bifunctional oxygen catalysts is crucial for zinc–air batteries (ZABs). High‐entropy materials have emerged to possess great potential as oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) bifunctional catalysts for ZABs, but its efficient synthesis with superior activity remains challenging. Herein, a rapid and facile microwave‐induced carbon thermal shock technique was developed to efficiently synthesize high‐entropy oxide (HEO) nanoparticles, i.e., (FeCoNiCrMn) ₃ O ₄ , that are uniformly anchored onto carbon nanotubes (CNT), denoted as (FeCoNiCrMn) ₃ O ₄ /CNT. The obtained (FeCoNiCrMn) ₃ O ₄ /CNT can work as a bifunctional catalyst, exhibiting excellent performance with the OER overpotential of 273 mV at 10 mA cm ⁻² and the ORR half‐wave potential of 0.771 V. Moreover, the ZAB assembled with (FeCoNiCrMn) ₃ O ₄ /CNT as the cathode demonstrates superior performance, with high specific capacity (828.8 mAh g _Zn ⁻¹ ), energy density (986.3 Wh kg _Zn ⁻¹ ), and outstanding long‐term durability exceeding 500 h. This work offers a scalable strategy in efficient construction of CNT‐supported HEO nanomaterials, thus facilitating the development of high‐efficiency electrocatalysts for practical ZAB applications.

Fe–Mn based layered transition metal oxides are compelling candidates for sodium-ion cathodes owing to their high specific capacity and cost-effectiveness.

Solid‐state metal batteries promise next‐generation energy storage with inherent safety and high energy density. However, instability at grain boundaries and surfaces critically hinders practical deployment in solid polycrystalline ion conductors. This work proposes a dual‐interface fluorination strategy through the incorporation of fluoride‐based grain boundary phases in solid electrolytes to simultaneously address these issues. The resulting NZSP‐MgF ₂ electrolyte exhibits a low electronic conductivity of 6.0 × 10 ⁻⁹ S cm ⁻¹ and a widened bandgap, effectively suppressing the formation and growth of internal dendrites. Meanwhile, the interfacial contact impedance of the ceramic electrolyte against the metallic Na electrode is significantly reduced to 11 Ω cm ² . Crucially, the fluorinated polycrystalline Na ₃ Zr ₂ Si ₂ PO ₁₂ ceramic electrolyte retains exceptional stability even after 30 days of exposure to air: symmetric sodium metal cells still exhibit low interfacial contact impedance (12 Ω cm ² ), high critical current density (1.0 mA cm ⁻² ), and stable cycling over 1100 h at 0.2 mA cm ⁻² . Furthermore, full cells paired with Na ₃ V ₂ (PO ₄ ) ₃ cathode demonstrate outstanding electrochemical performance with a capacity retention of 98.1% after 2000 cycles at 2 C. This work provides a general strategy to enhance air stability, dendrite suppression, and electrode compatibility of polycrystalline electrolyte, promoting the practical realization of solid‐state metal batteries.

Leveraging the slow-light effect in COF photonic crystals, the proposed sensing platform achieves a 10.34-fold fluorescence enhancement and a detection limit of 20.7 nM for TNP.

Sodium Superionic Conductor (NASICON) cathodes possess a favorable Na ⁺ diffusion pathway and structural stability, making them promising cathode materials for sodium‐ion batteries. However, upon electrochemical cycling V‐based and Mn‐based NASICON‐type cathodes still hold apparent drawbacks of lattice distortion and structural instability. In this work, a strategy of negative enthalpy doping has been developed to address these issues. Na _3.25 VMn _0.5 Ti _0.25 Al _0.25 (PO ₄ ) ₃ (NVMTAP) is proposed and prepared through multi‐element doping, which fully utilizes the reversible activation of the high‐voltage platforms of V ⁴⁺ /V ⁵⁺ and Mn ³⁺ /Mn ⁴⁺ . Moreover, excellent lattice structure stability with a cell volume variation of only 1.74% is achieved. The as‐designed NVMTAP can deliver a specific capacity of 136.3 mAh g ⁻¹ at 0.1 C with an energy density of 430 Wh kg ⁻¹ and a high‐capacity retention of 74.8% over 4000 cycles under an ultra‐high rate of 30 C (4.2 A g ⁻¹ ). Furthermore, the cathode also demonstrates excellent low‐temperature performance, with a capacity retention of 93.5% after 1000 cycles at 15 C and ‐20°C. This research provides a beneficial reference for enhancing the energy density of NASICON‐type electrode materials and simultaneously realizing robust structural stability.

The reaction mechanism for the photocatalytic reduction of TNP on H ₂₀₀ ZIF-8/TiO ₂ .