Iron-based mixed polyanion-type sodium-ion cathode materials like Na₄Fe₃(PO₄)₂P₂O₇ (NFPP) typically suffer from poor electronic conductivity, resulting in capacity retention under high-rate cycling and rapid capacity degradation. In this study, we introduce an innovative dual-carbon enhancement strategy that integrates carbon nanotubes (CNTs) into the precursor mixing stage, combined with citric acid as both an organic carbon source and a dispersant. Unlike conventional methods where CNTs are added post-synthesis or during slurry preparation—often leading to uneven dispersion—we incorporate CNTs during the initial mixing process. Citric acid not only provides carbon for pyrolysis but also forms a gel-like precursor that ensures homogeneous dispersion of CNTs and raw materials. This one-step sintering approach produces NFPP particles uniformly coated with carbon layers intimately connected to well-dispersed CNTs, potentially forming chemical bonds between them. The resulting pyrolytic carbon and CNT-coated NFPP (NFPP-CNT) exhibits a dense and interconnected electron-conductive network, significantly enhancing its electronic conductivity and electrochemical performance. The precisely designed NFPP-CNT delivers a reversible capacity of 111 mAh/g at 0.1 C and maintains a reversible capacity of 78.8 mAh/g even at an ultra-high rate of 100 C. NFPP-CNT also demonstrates outstanding high-rate capacity retention, with 85.7% capacity remaining after 27,000 cycles at 100 C. This novel synthesis method and the multifaceted role of citric acid endow NFPP with superior high-rate, long-cycle, and low-temperature performance, making it a highly competitive material for large-scale electric energy storage systems (EESs).

All-solid-state batteries, renowned for their enhanced safety and high energy density, have garnered broad interest. Oxide solid electrolytes are highly anticipated for their balanced performance. However, their high Young’s modulus and inadaptability to volume change during cycling lead to poor contact and eventual battery failure. In this work, Young’s modulus of Li_1+x(OH)_xCl samples is lowered to a level comparable to that of sulfide by regulating the –OH content. As the –OH content increases, Young’s modulus of Li_1+x(OH)_xCl samples decreases significantly. This may be due to the local aggregation of –OH groups, forming cavities similar to LiOH structure, which reduces the bonding of the structure. On the premise of high Li-ion conductivity and electrochemical stability, the lowered Young’s modulus improves the contact between the solid electrolyte and the electrodes, forming a strong and stable interfacial layer, thereby improving interfacial and cycling stability. The symmetrical lithium metal cell shows excellent cycle performance of 600 h, and the assembled LiFePO₄|Li_2.4(OH)_1.4Cl|Li cell shows significantly enhanced cycling endurance with 80% capacity retention after 150 cycles. This work not only emphasizes the crucial importance of Young’s modulus in improving interface issues but also offers innovative approaches to advance the mechanical properties of solid electrolytes.

Hierarchical WO₃ nanomesh, assembled from single-crystalline WO₃ nanowires, is prepared via a hydrothermal method using thiourea (Tu) as the morphology-controlling agent. Formation of the hierarchical architecture comprising of WO₃ nanowires takes place via Ostwald ripening mechanism with the growth orientation. The sensor based on WO₃ nanomesh has good electrical conductivity and is therefore suitable as NO₂ sensing material. The WO₃ nanomesh sensor exhibited high response, short response and recovery time, and excellent selectivity towards ppb-level NO₂ at low temperature of 160 ℃. The superior gas performance of the sensor was attributed to the high-purity hexagonal WO₃ with high specific surface area, which gives rise to enhanced surface adsorption sites for gas adsorption. The electron depletion theory was used for explaining the NO₂-sensing mechanism by the gas adsorption/desorption and charge transfer happened on the surface of WO₃ nanomesh.

Studying on the anode materials with high energy densities for next-generation lithium-ion batteries (LIBs) is the key for the wide application for electrochemical energy storage devices. Ti-based compounds as promising anode materials are known for their outstanding high-rate capacity and cycling stability as well as improved safety over graphite. However, Ti-based materials still suffer from the low capacity, thus largely limiting their commercialized application. Here, we present an overview of the recent development of Ti-based anode materials in LIBs, and special emphasis is placed on capacity enhancement by rational design of hybrid nanocomposites with conversion-/ alloying-type anodes. This review is expected to provide a guidance for designing novel Ti-based materials for energy storage and conversion.