Synergistic piezoelectricity enhanced BaTiO_(3)/polyacrylonitrile elastomer-based highly sensitive pressure sensor for intelligent sensing and posture recognition applications

Designing stretchable and skin-conformal self-powered sensors for intelligent sensing and posture recognition is challenging.Here,based on a multi-force mixing and vulcanization process,as well as synergistically piezoelectricity of BaTiO_(3)and polyacrylonitrile,an all-in-one,stretchable,and self-powered elastomer-based piezo-pressure sensor(ASPS)with high sensitivity is reported.The ASPS presents excellent sensitivity(0.93 V/104 Pa of voltage and 4.92 nA/104 Pa of current at a pressure of 10-200 kPa)and high durability(over 10,000 cycles).Moreover,the ASPS exhibits a wide measurement range,good linearity,rapid response time,and stable frequency response.All components were fabricated using silicone,affording satisfactory skinconformality for sensing postures.Through cooperation with a homemade circuit and artificial intelligence algorithm,an information processing strategy was proposed to realize intelligent sensing and recognition.The home-made circuit achieves the acquisition and wireless transmission of ASPS signals(transmission distance up to 50 m),and the algorithm realizes the classification and identification of ASPS signals(accuracy up to 99.5%).This study proposes not only a novel fabrication method for developing self-powered sensors,but also a new information processing strategy for intelligent sensing and recognition,which offers significant application potential in human-machine interaction,physiological analysis,and medical research.

Recent Progress of Functional Fiber and Textile Triboelectric Nanogenerators:Towards Electricity Power Generation and Intelligent Sensing

Rapid development in wearable electronics has brought huge convenience to human life and gradually penetrated into various indispensable felds,such as health monitoring,medical assistance,smart sports,object tracking and smart home,etc.However,the suitable energy supply system for these wearable electronics remains an important issue to address.Fiber and textile triboelectric nanogenerators(f/t-TENGs),capable of converting biomechanical energy into electricity,have promising features to act as a mobile sustainable power source for wearable electronics or directly serve as an intelligent self-powered sensing solution.Compared with the low-output piezoelectric nanogenerators,hard-to-wear electromagnetic generators and other bulk TENGs,the fber/textile TENG may be the best type of wearable human mechanical energy harvester at present.Herein,this review comprehensively introduces the recent progress of smart fbers and textiles with a highlight on triboelectric nanogenerators,including the general materials and structures of fber/textile shaped electronics,various fber and textile devices for triboelectric/triboelectric-integrated energy harvesting and self-powered smart sensing systems.Moreover,the advance of f/t-TENGs with multifunctionality and large-scale textile processing techniques is summarized as well.Finally,the challenges and perspectives of f/t-TENGs for future improvement,large-scale production and emerging applications are thoroughly discussed as well.

Multi-level intelligence empowering lithium-ion batteries

With the significant and widespread application of lithium-ion batteries,there is a growing demand for improved performances of lithium-ion batteries.The intricate degradation throughout the whole lifecycle profoundly impacts the safety,durability,and reliability of lithium-ion batteries.To ensure the long-term,safe,and efficient operation of lithium-ion batteries in various fields,there is a pressing need for enhanced battery intelligence that can withstand extreme events.This work reviews the current status of intelligent battery technology from three perspectives:intelligent response,intelligent sensing,and intelligent management.The intelligent response of battery materials forms the foundation for battery stability,the intelligent sensing of multi-dimensional signals is essential for battery management,and the intelligent management ensures the long-term stable operation of lithium-ion batteries.The critical challenges encountered in the development of intelligent battery technology from each perspective are thoroughly analyzed,and potential solutions are proposed,aiming to facilitate the rapid development of intelligent battery technologies.

Characteristic Study of Self-Powered Sensors Based on Native Protein Composite Film

Flexible electronic sensors composed of flexible film and conductive materials play an increasingly important role in wearable and internet information transmission.It has received more and more attention and made some progress over the decades.However,it is still a great challenge to prepare biocompatible and highly transparent conductive films.Egg white is a pure natural protein-rich material.Hydroxypropylmethyl cellulose has a good compatibility and high transparency,which is an ideal material for flexible sensors.Here,we overcome the problem of poor mechanical flexibility and electrical conductivity of protein,and develop a high transparency and good flexibility hydroxypropylmethyl cellulose/egg white protein composite membrane-based triboelectric nanogenerator('X'-TENG).The experimental results show that the flexible pressure sensor based on'X'-TENG has a high sensitivity,fast response speed,and low detection limit.It can even be used as a touch/pressure sensing artificial electronic skin.It can also be made into an intelligent waffle keyboard for recording and tracking users of the keyboard.Our strategy may provide a new way to easily build flexible electronic sensors and move toward practical applications.

Flexible antibacterial degradable bioelastomer nanocomposites for ultrasensitive human–machine interaction sensing enabled by machine learning

Flexible wearables have attracted extensive interests for personal human motion sensing,intelligent disease diagnosis,and multifunctional electronic skins.How-ever,the reported flexible sensors,mostly exhibited narrow detection range,low sensitivity,limited degradability to aggravate environmental pollution from vast electronic wastes,and poor antibacterial performance to hardly improve skin dis-comfort and skin inflammation from bacterial growth under long-term wearing.Herein,bioinspired from human skin featuring highly sensitive tactile sensation with spinous microstructures for amplifying sensing sensitivity between epidermis and dermis,a wearable antibacterial degradable electronics is prepared from degrad-able elastomeric substrate with MXene-coated spinous microstructures templated from lotus leaf assembled with the interdigitated electrode.The degradable elas-tomer is facilely obtained with tunable modulus to match the modulus of human skin with improved hydrophilicity for rapid degradation.The as-obtained sensor displays ultra-low detection limit(0.2 Pa),higher sensitivity(up to 540.2 kPa^(-1)),outstand-ing cycling stability(>23,000 cycles),a wide detection range,robust degradability,and excellent antibacterial capability.Facilitated by machine learning,the collected sensing signals from the integrated sensors on volunteer's fingers to the related American Sign Language are effectively recognized with an accuracy up to 99%,showing excellent potential in wireless human movement sensing and smart machine learning-enabled human-machine interaction.

Design and application of friction pair surface modification coating for remanufacturing

Friction,wear,and contact fatigue are the main causes of energy loss,material waste,and equipment failure.The aim of remanufacturing is to repair and modify the damaged equipment surface,and the surface coating is the major material that allows the remanufactured parts to be used in a new round of operation.Thus,the design and preparation of surface coatings are very important to repair,strengthen,or modify the friction pairs,in order to ensure long-term operation of the remanufactured parts.Recent1y,a lot of research on designing and preparing friction pair surface modification coatings has been conducted by the National Key Laboratory for Remanufacturing (NKLR).The research conducted achieved the following goals:the mechanism of micro/nano multilayer surface modification coatings with long-term efficacy life was revealed,and the corresponding design considerations and preparation methods of nanocrystalline micro tribological coatings were innovatively developed.A series of new 'two-step' processes to prepare sulfide solid lubricating coatings were developed.The competitive failure mechanism of the surface coating in simultaneous wear and fatigue conditions was revealed,and some composite coatings with dual properties of wear resistance and fatigue resistance were prepared.Based on the stress distribution of friction surface contact areas and the piezoelectric effect,a failure warning intelligent coating is designed and developed.These coatings have been successfully applied to critical friction components,such as the spindle of large centrifugal compressors,engine cylinder piston components,and driver gear pairs.