Two positive effects with one arrow:Modulating crystal and interfacial decoration towards high-potential cathode material

As the primary suppliers of cyclable sodium ions,O3-type layer-structured manganese-based oxides are recognized as highly competitive cathode candidates for sodium-ion batteries.To advance the development of high-energy sodium-ion batteries,it is crucial to explore cathode materials operating at high voltages while maintaining a stable cycling behavior.The orbital and electronic structure of the octahedral center metal element plays a crucial role in maintaining the octahedra structural integrity and improving Na^(+)ion diffusion by introducing heterogeneous chemical bonding.Inspired by the abundant configuration of extra nuclear electrons and large ion radius,we employed trace amounts of tungsten in this study.The obtained cathode material can promote the reversibility of oxygen redox reactions in the high-voltage region and inhibit the loss of lattice oxygen.Additionally,the formation of a Na_(2)WO_(4) coating on the material surface can improve the interfacial stability and interface ions diffusion.It demonstrates an initial Coulombic efficiency(ICE)of 94.6%along with 168.5 mA h g^(-1 )discharge capacity within the voltage range of 1.9-4.35 V.These findings contribute to the advancement of high-energy sodium-ion batteries by providing insights into the benefits of tungsten doping and Na_(2)WO_(4) coating on cathode materials.

Boosting nitrogen electrocatalytic fixation by three-dimensional TiO_(2-δ)N_δnanowire arrays

Owing to the environmental and inherent advantages,nitrogen reduction reaction(NRR)by electrocatalysts attracts global attention.The surface engineering is widely employed to enhance the electrocatalytic activity by atomic defects and heterostructure effects.A three-dimensional(3D)free-standing integrated electrode was fabricated by numerous nearly-single-crystal TiO_(2-δ)N_δnanowire arrays.Based on the high electronic conductivity network,it exposes numerous active sites as well to facilitate the selective nitrogen adsorption and*H adsorption suppression.The synergistic effects between Ti^(3+)and oxygen vacancy(O_v)boost the intrinsic catalytic activity,in which Ti^(3+)acquired electrons via Ovcan effectively activate the N≡N bond and make it easy to bind with protons.The energy barrier of primary protonation process(*N_(2)+H^(+)+e^(-)→*NNH)can be dramatically decreased.The highest ammonia yield rate(14.33μg h^(-1)mgcat^(-1))emerges at-0.2 V,while the optimal ammonia Faradaic efficiency(9.17%)is acquired at-0.1 V.Density functional theory(DFT)calculation reveals that the Ti^(3+)can be served as the active sites for nitrogen adsorption and activation,while ammonia synthesis is accomplished by the distal pathway.The high electronic conductivity integrated network and synergistic effects can significantly facilitate nitrogen absorption and accelerate electrocatalytic reaction kinetic,which are responsible for the excellent NRR performance at room temperature.

Research Progress and Future Perspectives on Rechargeable Na-O_(2) and Na-CO_(2) Batteries

Rechargeable sodium–oxygen(Na-O_(2))and sodium–carbon dioxide(Na-CO_(2))batteries have attracted intensive research attention in recent years owing to their advantages of high theoretical energy density,modest cost,abundance of sodium resources,and promising potential for achieving real sodium–air batteries in large-scale energy storage systems.Nevertheless,current research on Na-O_(2)and Na-CO_(2)batteries is facing enormous challenges,such as low energy efficiency and limited cycle life,which are restricting their progress at the initial stage.Therefore,understanding their working principles,and the chemical and electrochemical reactions of the electrodes is indispensable to achieve their practical application and even the goal of true sodium–air batteries.This review aims to provide an overview of the research developments and future perspectives on Na-O_(2)and Na-CO_(2)batteries,which include the major aspects,such as working mechanisms,air cathode materials design strategies,sodium anode protection,and electrolyte stability.Moreover,the remaining issues and future research directions are also thoroughly discussed and presented.

Magnetoelectric coupling effect of polarization regulation in BiFeO_(3)/LaTiO_(3)heterostructures

An effective regulation of the magnetism and interface of ferromagnetic materials is not only of great scientific significance,but also has an urgent need in modern industry.In this work,by using the first-principles calculations,we demonstrate an effective approach to achieve non-volatile electrical control of ferromagnets,which proves this idea in multiferroic heterostructures of ferromagnetic La TiO_(3)and ferroelectric Bi FeO_(3).The results show that the magnetic properties and two-dimensional electron gas concentrations of La TiO_(3)films can be controlled by changing the polarization directions of Bi FeO_(3).The destroyed symmetry being introduced by ferroelectric polarization of the system leads to the transfer and reconstruction of the Ti-3 d electrons,which is the fundamental reason for the changing of magnetic properties.This multiferroic heterostructures will pave the way for non-volatile electrical control of ferromagnets and have potential applications.

N-doped graphitic carbon encapsulating cobalt nanoparticles derived from novel metal–organic frameworks for electrocatalytic oxygen evolution reaction

Nitrogen-doped carbon catalysts with hierarchical porous structure are promising oxygen evolution reaction(OER)catalysts due to the faster mass transfer and better charge carrying ability.Herein,an exquisite high nitrogen-containing ligand was designed and readily synthesized from the low-cost biomolecule adenine.Accordingly,three new MOFs(TJU-103,TJU-104 and TJU-105)were prepared using the Co(II)or Mn(II)ions as metal nodes.Through rationally controlling pyrolysis condition,in virtue of the high nitrogen content in well-defined periodic structure of the pristine MOFs,TJU-104–900 among the derived MOFs with hierarchical porous structure,i.e.,N-doped graphitic carbon encapsulating homogeneously distributed cobalt nanoparticles,could be conveniently obtained.Thanks to the synergistic effect of the hierarchical structure and well dispersed active components(i.e.,C=O,Co–Nx,graphitic C and N,pyridinic N),it could exhibit an overpotential of 280 mV@10mA/cm^(2)on carbon cloth for OER activity.This work provides the inspiration for fabrication of nitrogen-doped carbon/metal electrocatalysts from cost-effective and abundant biomolecules,which is promising for practical OER application.

界面优化实现寿命超过20年的有机太阳电池

近年来,由于新型非富勒烯受体材料的快速发展,诸多中国科学家在有机太阳电池(OPV)的能量转换效率(PCE)上取得了重大突破.为了实现OPV的产业化,目前亟待解决的难题在于提升OPV的使用寿命,并降低大面积模组器件的效率滚降.本文提出了一种简易而有效的阴极界面修饰方法,成功实现了非富勒烯有机太阳电池超过20年的使用寿命.文章采用自组装小分子C60-SAM对氧化锌阴极界面进行修饰,不仅可以调控氧化锌和活性层之间的表面能匹配及其分子间相互作用来得到形貌更稳定的器件,同时还能通过钝化氧化锌表面缺陷以提升电池器件的电荷抽取效率.在此基础上,作者基于PTB7-Th:IEICO-4F制备得到PCE=10%,持续光照下寿命长达34000 h的OPV器件.根据中国平均每年1500 kWh/m2太阳辐射量推算,该OPV器件的使用寿命可超过20年.这将为OPV技术实现商业化带来极强曙光.