Difficulties, strategies, and recent research and development of layered sodium transition metal oxide cathode materials for high-energy sodium-ion batteries

Energy-storage systems and their production have attracted significant interest for practical applications.Batteries are the foundation of sustainable energy sources for electric vehicles(EVs),portable electronic devices(PEDs),etc.In recent decades,Lithium-ion batteries(LIBs) have been extensively utilized in largescale energy storage devices owing to their long cycle life and high energy density.However,the high cost and limited availability of Li are the two main obstacles for LIBs.In this regard,sodium-ion batteries(SIBs) are attractive alternatives to LIBs for large-scale energy storage systems because of the abundance and low cost of sodium materials.Cathode is one of the most important components in the battery,which limits cost and performance of a battery.Among the classified cathode structures,layered structure materials have attracted attention because of their high ionic conductivity,fast diffusion rate,and high specific capacity.Here,we present a comprehensive review of the classification of layered structures and the preparation of layered materials.Furthermore,the review article discusses extensively about the issues of the layered materials,namely(1) electrochemical degradation,(2) irreversible structural changes,and(3) structural instability,and also it provides strategies to overcome the issues such as elemental phase composition,a small amount of elemental doping,structural design,and surface alteration for emerging SIBs.In addition,the article discusses about the recent research development on layered unary,binary,ternary,quaternary,quinary,and senary-based O3-and P2-type cathode materials for high-energy SIBs.This review article provides useful information for the development of high-energy layered sodium transition metal oxide P2 and O3-cathode materials for practical SIBs.

Enhanced performance of solution-processed carbon nanotube transparent electrodes in foldable perovskite solar cells through vertical separation of binders by using eco-friendly parylene substrate

The successful utilization of an eco-friendly and biocompatible parylene-C substrate for high-performance solution-processed double-walled carbon nanotube(CNT)electrode-based perovskite solar cells(PSCs)was demonstrated.Through the use of a novel inversion transfer technique,vertical separation of the binders from the CNTs was induced,rendering a stronger p-doping effect and thereby a higher conductivity of the CNTs.The resulting foldable devices exhibited a power conversion efficiency of 18.11%,which is the highest reported among CNT transparent electrode-based PSCs to date,and withstood more than 10,000 folding cycles at a radius of 0.5 mm,demonstrating unprecedented mechanical stability.Furthermore,solar modules were fabricated using entirely laser scribing processes to assess the potential of the solution-processable nanocarbon electrode.Notably,this is the only one to be processed entirely by the laser scribing process and to be biocompatible as well as eco-friendly among the previously reported nonindium tin oxide-based perovskite solar modules.

Patterning of Metal Halide Perovskite Thin Films and Functional Layers for Optoelectronic Applications

In recent years,metal halide perovskites have received significant attention as materials for next-generation optoelectronic devices owing to their excellent optoelectronic properties.The unprecedented rapid evolution in the device performance has been achieved by gaining an advanced understanding of the composition,crystal growth,and defect engineering of perovskites.As device performances approach their theoretical limits,effective optical management becomes essential for achieving higher efficiency.In this review,we discuss the status and perspectives of nano to micron-scale patterning methods for the optical management of perovskite optoelectronic devices.We initially discuss the importance of effective light harvesting and light outcoupling via optical management.Subsequently,the recent progress in various patterning/texturing techniques applied to perovskite optoelectronic devices is summarized by categorizing them into top-down and bottom-up methods.Finally,we discuss the perspectives of advanced patterning/texturing technologies for the development and commercialization of perovskite optoelectronic devices.

A study of highly activated hydrogen evolution reaction performance in acidic media by 2D heterostructure of N and S doped graphene on MoO_(x)

Herein,a layer of molybdenum oxide(MoO_(x)),a transition metal oxide(TMO),which has outstanding catalytic properties in combination with a carbonbased thin film,is modified to improve the hydrogen production performance and protect the MoO_(x)in acidic media.A thin film of graphene is transferred onto the MoO_(x)layer,after which the graphene structure is doped with N and S atoms at room temperature using a plasma doping method to modify the electronic structure and intrinsic properties of the material.The oxygen functional groups in graphene increase the interfacial interactions and electrical contacts between graphene and MoO_(x).The appearance of surface defects such as oxygen vacancies can result in vacancies in MoO_(x).This improves the electrical conductivity and electrochemically accessible surface area.Increasing the number of defects in graphene by adding dopants can significantly affect the chemical reaction at the interfaces and improve the electrochemical performance.These defects in graphene play a crucial role in the adsorption of H^(+)ions on the graphene surface and their transport to the MoO_(x)layer underneath.This enables MoO_(x)to participate in the reaction with the doped graphene.N^(‐)and S^(‐)doped graphene(NSGr)on MoO_(x)is active in acidic media and performs well in terms of hydrogen production.The initial overpotential value of 359 mV for the current density of−10 mA/cm^(2)is lowered to 228 mV after activation.

Beta-phase transformation of polyvinylidene fluoride with supersonically sprayed ZnSnO_(3) cuboids for flexible piezoelectric nanogenerators

Flexible self-powered electromechanical devices,such as piezoelectric nanogenerators(PENGs),which are used in wearable and implantable devices,are emerging as state-of-the-art clean energy sources.In this study,a scalable supersonic spraying technique was used to prepare flexible piezocomposite films of polyvinylidene fluoride(PVDF)and hydrothermally synthesized ZnSnO_(3)(ZSO)cubes for PENGs.Raman spectra confirmed that the transformation of the α-phase of PVDF to its β-phase was induced by the shear stress generated between the ZSO particles and PVDF polymer during supersonic spraying.The op-timized sample comprising 0.43 g of ZSO cubes and 1 g of PVDF produced a maximum piezopotential of 41.5 V and a short-circuit current,I_(sc),of 52.5 μA.A maximum power density of 50.6 μW cm-2 was ob-tained at a loading resistance of 0.4 MΩ,which matched the impedance of the PENG.Long-term tapping and bending cycles of N_(tap)=4200 and N_(bend)=600 yielded piezopotentials of 40.5 and 1.7 V,respectively.In addition,electrical poling for 2 h increased the piezopotential to 52 V owing to the alignment of the ferroelectric dipoles in the PVDF.

Dual-logic-in-memory implementation with orthogonal polarization of van der Waals ferroelectric heterostructure

The rapid advancement of AI-enabled applications has resulted in an increasing need for energy-efficient computing hardware.Logic-in-memory is a promising approach for processing the data stored in memory,wherein fast and efficient computations are possible owing to the parallel execution of reconfigurable logic operations.In this study,a dual-logic-in-memory device,which can simultaneously perform two logic operations in four states,is demonstrated using van der Waals ferroelectric field-effect transistors(vdW FeFETs).The proposed dual-logic-in-memory device,which also acts as a twobit storage device,is a single bidirectional polarization-integrated ferroelectric field-effect transistor(BPI-FeFET).It is fabricated by integrating an in-plane vdW ferroelectric semiconductor SnS and an out-of-plane vdW ferroelectric gate dielectric material—CuInP_(2)S_(6).Four reliable resistance states with excellent endurance and retention characteristics were achieved.The two-bit storage mechanism in a BPI-FeFET was analyzed from two perspectives:carrier density and carrier injection controls,which originated from the out-of-plane polarization of the gate dielectric and in-plane polarization of the semiconductor,respectively.Unlike conventional multilevel FeFETs,the proposed BPIFeFET does not require additional pre-examination or erasing steps to switch from/to an intermediate polarization,enabling direct switching between the four memory states.To utilize the fabricated BPI-FeFET as a dual-logic-inmemory device,two logical operations were selected(XOR and AND),and their parallel execution was demonstrated.Different types of logic operations could be implemented by selecting different initial states,demonstrating various types of functions required for numerous neural network operations.The flexibility and efficiency of the proposed dual-logic-in-memory device appear promising in the realization of next-generation low-power computing systems.

Advances in CIGS thin film solar cells with emphasis on the alkali element post-deposition treatment

In the past tens of years,the power conversion efficiency of Cu(In,Ga)Se2(CIGS)has continuously improved and been one of the fastest growing photovoltaic technologies that can also help us achieve the goal of carbon emissions reduction.Among several key advances,the alkali element post-deposition treatment(AlK PDT)is regarded as the most important finding in the last 10 years,which has led to the improvement of CIGS solar cell efficiency from 20.4%to 23.35%.A profound understanding of the influence of alkali element on the chemical and electrical properties of the CIGS absorber along with the underlying mechanisms is of great importance.In this review,we summarize the strategies of the alkali element doping in CIGS solar cell,the problems to be noted in the PDT process,the effects on the CdS buffer layer,the effects of different alkali elements on the structure and morphology of the CIGS absorber layer,and retrospect the progress in the CIGS solar cell with emphasis on the alkali element post deposition treatment.

The Tomato Hybrid Proline-rich Protein regulates the abscission zone competence to respond to ethylene signals

The Tomato Hybrid Proline-rich Protein(THyPRP)gene was specifically expressed in the tomato(Solanum lycopersicum)flower abscission zone(FAZ),and its stable antisense silencing under the control of an abscission zone(AZ)-specific promoter,Tomato Abscission Polygalacturonase4,significantly inhibited tomato pedicel abscission following flower removal.For understanding the THyPRP role in regulating pedicel abscission,a transcriptomic analysis of the FAZ of THyPRP-silenced plants was performed,using a newly developed AZ-specific tomato microarray chip.Decreased expression of THyPRP in the silenced plants was already observed before abscission induction,resulting in FAZ-specific altered gene expression of transcription factors,epigenetic modifiers,post-translational regulators,and transporters.Our data demonstrate that the effect of THyPRP silencing on pedicel abscission was not mediated by its effect on auxin balance,but by decreased ethylene biosynthesis and response.Additionally,THyPRP silencing revealed new players,which were demonstrated for the first time to be involved in regulating pedicel abscission processes.These include:gibberellin perception,Ca2+-Calmodulin signaling,Serpins and Small Ubiquitin-related Modifier proteins involved in post-translational modifications,Synthaxin and SNARE-like proteins,which participate in exocytosis,a process necessary for cell separation.These changes,occurring in the silenced plants early after flower removal,inhibited and/or delayed the acquisition of the competence of the FAZ cells to respond to ethylene signaling.Our results suggest that THyPRP acts as a master regulator of flower abscission in tomato,predominantly by playing a role in the regulation of the FAZ cell competence to respond to ethylene signals.

High-performance 110 kVp hard x-ray detector based on all-crystalline-surface passivated perovskite single crystals

Halide perovskite single crystals(SCs)have attracted much attention for their application in high-performance x-ray detectors owing to their desirable properties,including low defect density,high mobility–lifetime product(μτ),and long carrier diffusion length.However,suppressing the inherent defects in perovskites and overcoming the ion migration primarily caused by these defects remains a challenge.This study proposes a facile process for dipping Cs0.05FA0.9MA0.05PbI3 SCs synthesized by a solution-based inverse temperature crystallization method into a 2-phenylethylammonium iodide(PEAI)solution to reduce the number of defects,inhibit ion migration,and increase x-ray sensitivity.Compared to conventional spin coating,this simple dipping process forms a two-dimensional PEA2PbI4 layer on all SC surfaces without further treatment,effectively passivating all surfaces of the inherently defective SCs and minimizing ion migration.As a result,the PEAI-treated perovskite SC-based x-ray detector achieves a record x-ray sensitivity of 1.3×10^(5)μC Gyair^(-1) cm^(-2) with a bias voltage of 30 V at realistic clinical dose rates of 1–5 mGy s^(-1)(peak potential of 110 kVp),which is 6 times more sensitive than an untreated SC-based detector and 3 orders of magnitude more sensitive than a commercialα-Se-based detector.Furthermore,the PEAI-treatedperovskite SC-based x-ray detector exhibits a low detection limit(73 nGy s^(-1)),improved x-ray response,and clear x-ray images by a scanning method,highlighting the effectiveness of the PEAI dipping approach for fabricating next-generation x-ray detectors.

Surface-modified barium titanate by MEEAA for high-energy storage application of polymer composites

In this study,2-[2-(2-methoxyethoxy)ethoxy]acetic acid(MEEAA)was used to modify the surface of barium titanate nanoparticles(BT NPs)to enhance the compatibility and dispersion of the BT ceramic fillers in polymer matrix.A uniform coating layer with a thickness about 2 nm was formed on the surface of BT after modification.The poly(vinylidene fluoride)-hexafluoropropene[P(VDF-HFP)]composites filled with MEEAA-modified BT NPs achieved higher permittivity(∼13 at 3.0 vol%filler)and discharged energy density than that of the untreated BT filled composite.The maximum discharge energy density of 7.8 J/cm^(3)was obtained in the nanocomposites with 3 vol%MEEAA-modified BT NPs at electric field of 425 kV/mm,which is 77%higher than that of 4.4 J/cm^(3)of pure P(VDF-HFP)film at electric field of 420 kV/mm.

4.3%铜锌锡硫硒太阳能电池组件

铜锌锡硫硒半导体材料组成元素储量丰富、绿色环保、稳定性高,由其制备的薄膜太阳能电池效率已接近15%的商业化基准线.然而,目前铜锌锡硫硒太阳能电池的研究主要集中于有效面积小于1 cm~2的单节电池,面向商业化应用的组件还未见报道.本文报道面积10.5 cm~2的铜锌锡硫硒太阳能电池组件,该组件基于二甲亚砜前体溶液法制备,效率达到4.25%.与单节电池相比,效率损失率为56.8%.扫描电子显微镜形貌及元素组成分析结果表明:通过激光(P1,P2)和机械(P3)划线成功实现了模块化和串联集成;溶液制备工艺在P1凹槽沉积了更厚的吸收层,有利于降低横向电荷传输电阻;在皮秒激光划线下未观察到吸收层材料的金属化.组件的成功制备将铜锌锡硫硒薄膜太阳能电池向实际应用推进了一步.

A machine learning-assisted multifunctional tactile sensor for smart prosthetics

The absence of tactile perception limits the dexterity of a prosthetic hand and its acceptance by amputees.Recreating the sensing properties of the skin using a flexible tactile sensor could have profound implications for prosthetics,whereas existing tactile sensors often have limited functionality with cross-interference.In this study,we propose a machine-learning-assisted multifunctional tactile sensor for smart prosthetics,providing a human-like tactile sensing approach for amputations.This flexible sensor is based on a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)-melamine sponge,which enables the detection of force and temperature with low cross-coupling owing to two separate sensing mechanisms:the open-circuit voltage of the sensor as a force-insensitive intrinsic variable to measure the absolute temperature and the resistance as a temperature-insensitive extrinsic variable to measure force.Furthermore,by analyzing the unsteady heat conduction and characterizing it using real-time thermal imaging,we demonstrated that the process of open-circuit voltage variation resulting from the unsteady heat conduction is closely correlated with the heatconducting capabilities of materials,which can be utilized to discriminate between substances.Assisted by the decision tree algorithm,the device is endowed with thermal conductivity sensing ability,which allows it to identify 10 types of substances with an accuracy of 94.7%.Furthermore,an individual wearing an advanced myoelectric prosthesis equipped with the above sensor can sense pressure,temperature,and recognize different materials.We demonstrated that our multifunctional tactile sensor provides a new strategy to help amputees feel force,temperature and identify the material of objects without the aid of vision.

Towards the optimal interstitial doping for halide perovskites

Interstitial doping has been considered as an effective strategy to passivate and immobilize the ionic defects of metal halide perovskites to enhance performance and stability of perovskite solar cells.However,high dopant dosage causes lattice distortion which results in micro-strain and subsequent phase destabilization.This highlight discusses the latest report regarding optimal interstitial doping with a multivalent alkali metal cation for perovskites and awaiting issues associated with it.

Boron nitride microsphere/epoxy composites with enhanced thermal conductivity

As modern electronics are developed towards miniaturisation,high-degree integration and intelligentisation,a large amount of heat will be generated during the operation of devices.How to efficiently remove needless heat is becoming more and more crucial for the lifetime and performance of electronic devices.Many efforts have been made to improve the thermal conductivity of polymer composites,which is an important component of electronics.Herein,the authors report on preparation of boron nitride micosphere/epoxy composites.The cross-plane thermal conductivity of the resultant composites is up to 1.03 Wm‒1K‒1.This is attributed to the thermally conductive network formed by the peeled hexagonal boron nitride flakes.Thanks to the superior thermal stability of boron nitride micosphere,the boron nitride micosphere/epoxy composite shows a decreased coefficient of thermal expansion(53.47 ppm/K)and an increased glass transition temperature(147.2℃)compared with the pure epoxy resin.In addition,the boron nitride micosphere/epoxy composite exhibits a lower dielectric constant compared with that of the hexagonal boron nitride/epoxy composite.This strategy can potentially pave the way for the design and fabrication of materials with high cross-plane thermal conductivity and lower dielectric properties.