Hierarchically Structured Nb_(2)O_5 Microflowers with Enhanced Capacity and Fast-Charging Capability for Flexible Planar Sodium Ion Micro-Supercapacitors

Planar Na ion micro-supercapacitors(NIMSCs) that offer both high energy density and power density are deemed to a promising class of miniaturized power sources for wearable and portable microelectron-ics. Nevertheless, the development of NIMSCs are hugely impeded by the low capacity and sluggish Na ion kinetics in the negative electrode.Herein, we demonstrate a novel carbon-coated Nb_(2)O_5 microflower with a hierarchical structure composed of vertically intercrossed and porous nanosheets, boosting Na ion storage performance. The unique structural merits, including uniform carbon coating, ultrathin nanosheets and abun-dant pores, endow the Nb_(2)O_5 microflower with highly reversible Na ion storage capacity of 245 mAh g^(-1) at 0.25 C and excellent rate capability.Benefiting from high capacity and fast charging of Nb_(2)O_5 microflower, the planar NIMSCs consisted of Nb_(2)O_5 negative electrode and activated car-bon positive electrode deliver high areal energy density of 60.7 μWh cm^(-2),considerable voltage window of 3.5 V and extraordinary cyclability. Therefore, this work exploits a structural design strategy towards electrode materials for application in NIMSCs, holding great promise for flexible microelectronics.

A Thermoregulatory Flexible Phase Change Nonwoven for All‑Season High‑Efficiency Wearable Thermal Management

Phase change materials have a key role for wearable thermal management,but suffer from poor water vapor permeability,low enthalpy value and weak shape stability caused by liquid phase leakage and intrinsic rigidity of solid–liquid phase change materials.Herein,we report for the first time a versatile strategy for designed assembly of high-enthalpy flexible phase change nonwovens(GB-PCN)by wet-spinning hybrid grapheneboron nitride(GB)fiber and subsequent impregnating paraffins(e.g.,eicosane,octadecane).As a result,our GB-PCN exhibited an unprecedented enthalpy value of 206.0 J g^(−1),excellent thermal reliability and anti-leakage capacity,superb thermal cycling ability of 97.6%after 1000 cycles,and ultrahigh water vapor permeability(close to the cotton),outperforming the reported PCM films and fibers to date.Notably,the wearable thermal management systems based on GB-PCN for both clothing and face mask were demonstrated,which can maintain the human body at a comfortable temperature range for a significantly long time.Therefore,our results demonstrate huge potential of GB-PCN for human-wearable passive thermal management in real scenarios.

Two‑Dimensional Mesoporous Materials for Energy Storage and Conversion:Current Status,Chemical Synthesis and Challenging Perspectives

Two-dimensional(2D)mesoporous materials(2DMMs),defined as 2D nanosheets with randomly dispersed or orderly aligned mesopores of 2–50 nm,can synergistically combine the fascinating merits of 2D materials and mesoporous mate-rials,while overcoming their intrinsic shortcomings,e.g.,easy self-stacking of 2D materials and long ion transport paths in bulk mesoporous materials.These unique features enable fast ion diffusion,large specific surface area,and enriched adsorption/reaction sites,thus offering a promising solution for designing high-performance electrode/catalyst materials for next-generation energy storage and conversion devices(ESCDs).Herein,we review recent advances of state-of-the-art 2DMMs for high-efficiency ESCDs,focusing on two different configurations of in-plane mesoporous nanosheets and sandwich-like mesoporous heterostructures.Firstly,a brief introduction is given to highlighting the structural advantages(e.g.,tailored chemical composition,sheet configuration,and mesopore geometry)and key roles(e.g.,active materials and functional additives)of 2DMMs for high-performance ESCDs.Secondly,the chemical synthesis strategies of 2DMMs are summarized,including template-free,2D-template,mesopore-template,and 2D mesopore dual-template methods.Thirdly,the wide applications of 2DMMs in advanced supercapacitors,rechargeable batteries,and electrocatalysis are discussed,enlightening their intrinsic structure–property relationships.Finally,the future challenges and perspectives of 2DMMs in energy-related fields are presented.