Accuracy comparison and improvement for state of health estimation of lithium-ion battery based on random partial recharges and feature engineering

State of health(SOH)estimation of e-mobilities operated in real and dynamic conditions is essential and challenging.Most of existing estimations are based on a fixed constant current charging and discharging aging profiles,which overlooked the fact that the charging and discharging profiles are random and not complete in real application.This work investigates the influence of feature engineering on the accuracy of different machine learning(ML)-based SOH estimations acting on different recharging sub-profiles where a realistic battery mission profile is considered.Fifteen features were extracted from the battery partial recharging profiles,considering different factors such as starting voltage values,charge amount,and charging sliding windows.Then,features were selected based on a feature selection pipeline consisting of filtering and supervised ML-based subset selection.Multiple linear regression(MLR),Gaussian process regression(GPR),and support vector regression(SVR)were applied to estimate SOH,and root mean square error(RMSE)was used to evaluate and compare the estimation performance.The results showed that the feature selection pipeline can improve SOH estimation accuracy by 55.05%,2.57%,and 2.82%for MLR,GPR and SVR respectively.It was demonstrated that the estimation based on partial charging profiles with lower starting voltage,large charge,and large sliding window size is more likely to achieve higher accuracy.This work hopes to give some insights into the supervised ML-based feature engineering acting on random partial recharges on SOH estimation performance and tries to fill the gap of effective SOH estimation between theoretical study and real dynamic application.

Continuous roll-to-roll patterning of three-dimensional periodic nanostructures

In this work,we introduce a roll-to-roll system that can continuously print three-dimensional(3D)periodic nanostructures over large areas.This approach is based on Langmuir-Blodgett assembly of colloidal nanospheres,which diffract normal incident light to create a complex intensity pattern for near-field nanolithography.The geometry of the 3D nanostructure is defined by the Talbot effect and can be precisely designed by tuning the ratio of the nanosphere diameter to the exposure wavelength.Using this system,we have demonstrated patterning of 3D photonic crystals with a 500 nm period on a 50×200 mm^(2) flexible substrate,with a system throughput of 3mm/s.The patterning yield is quantitatively analyzed by an automated electron beam inspection method,demonstrating long-term repeatability of an up to 88% yield over a 4-month period.The inspection method can also be employed to examine pattern uniformity,achieving an average yield of up to 78.6% over full substrate areas.The proposed patterning method is highly versatile and scalable as a nanomanufacturing platform and can find application in nanophotonics,nanoarchitected materials,and multifunctional nanostructures.

Opto-thermoelectric pulling of light-absorbing particles

Optomechanics arises from the photon momentum and its exchange with low-dimensional objects.It is well known that optical radiation exerts pressure on objects,pushing them along the light path.However,optical pulling of an object against the light path is still a counter-intuitive phenomenon.Herein,we present a general concept of optical pulling-opto-thermoelectric pulling(OTEP)—where the optical heating of a light-absorbing particle using a simple plane wave can pull the particle itself against the light path.This irradiation orientation-directed pulling force imparts self-restoring behaviour to the particles,and three-dimensional(3D)trapping of single particles is achieved at an extremely low optical intensity of 10^(−2)mWμm^(−2).Moreover,the OTEP force can overcome the short trapping range of conventional optical tweezers and optically drive the particle flow up to a macroscopic distance.The concept of selfinduced opto-thermomechanical coupling is paving the way towards freeform optofluidic technology and lab-on-achip devices.

Atomistic modeling and rational design of optothermal tweezers for targeted applications

Optical manipulation of micro/nanoscale objects is of importance in life sciences,colloidal science,and nanotechnology.Optothermal tweezers exhibit superior manipulation capability at low optical intensity.However,our implicit understanding of the working mechanism has limited the further applications and innovations of optothermal tweezers.Herein,we present an atomistic view of opto-thermo-electro-mechanic coupling in optothermal tweezers,which enables us to rationally design the tweezers for optimum performance in targeted applications.Specifically,we have revealed that the non-uniform temperature distribution induces water polarization and charge separation,which creates the thermoelectric field dominating the optothermal trapping.We further design experiments to systematically verify our atomistic simulations.Guided by our new model,we develop new types of optothermal tweezers of high performance using low-concentrated electrolytes.Moreover,we demonstrate the use of new tweezers in opto-thermophoretic separation of colloidal particles of the same size based on the difference in their surface charge,which has been challenging for conventional optical tweezers.With the atomistic understanding that enables the performance optimization and function expansion,optothermal tweezers will further their impacts.

Optical Patterning of Two-Dimensional Materials

Recent advances in the field of two-dimensional(2D)materials have led to new electronic and photonic devices enabled by their unique properties at atomic thickness.Structuring 2D materials into desired patterns on substrates is often an essential and foremost step for the optimum performance of the functional devices.In this regard,optical patterning of 2D materials has received enormous interest due to its advantages of high-throughput,site-specific,and on-demand fabrication.Recent years have witnessed scientific reports of a variety of optical techniques applicable to patterning 2D materials.In this minireview,we present the state-of-the-art optical patterning of 2D materials,including laser thinning,doping,phase transition,oxidation,and ablation.Several applications based on optically patterned 2D materials will be discussed as well.With further developments,optical patterning is expected to hold the key in pushing the frontiers of manufacturing and applications of 2D materials.

Harnessing the flatbandλ-Ti_(3)O_(5):A breakthrough in solar steam generation

As global population rises,accompanied by escalating environmental pollution and climate change,numerous countries find themselves grappling with an acute scarcity of natural freshwater resources^([1]).Seawater desalination presents a compelling solution to this looming crisis,especially considering the oceans are Earth’s largest water reservoir^([2]).

Advancing optothermal manipulation:decoupling temperature and flow fields in quasi-isothermal microscale streaming

By decoupling temperature and flow fields through symmetry-correlated laser scan sequences,ISO-FLUCS enables quasi-isothermal optofluidic microscale streaming.This technique offers precise control over fluid manipulation while minimizing thermal damage.

Breaking boundaries in optical manipulation:beyond Nobel-Prize-winning tweezers

Richard Feynman’s famous 1959 lecture“There is plenty of room at the bottom”inspired scientists and engineers to focus on manipulating matter at the nanoscale[1].Optical tweezers,groundbreaking tools that use light to trap and move small particles with nanoscale precision,have revolutionized many fields such as materials science,biology,physics,and nanotechnology[2,3].For example,optical tweezers have enabled researchers to investigate the mechanical properties of biological molecules,study the behavior of colloidal suspensions,explore the movement of motor proteins,and investigate the directed assembly of nanoscale structures[4–6].

Unveiling the size effect of nitrogen-doped carbon-supported copper-based catalysts on nitrate-to-ammonia electroreduction

The electrocatalytic nitrate reduction reaction(NitRR)represents a promising approach toward achieving economically and environmentally sustainable ammonia.However,it remains a challenge to regulate the size effect of electrocatalysts to optimize the catalytic activity and ammonia selectivity.Herein,the Cu-based catalysts were tailored at the atomic level to exhibit a size gradient ranging from single-atom catalysts(SACs,0.15–0.35 nm)to single-cluster catalysts(SCCs,1.0–2.8 nm)and nanoparticles(NPs,20–30 nm),with the aim of studying the size effect for the NO_(3)^(-)-to-NH_(3) reduction reaction.Especially,the Cu SCCs exhibit enhanced metal–substrate and metal–metal interactions by taking advantageous features of Cu SACs and Cu NPs.Thus,Cu SCCs achieve exceptional electrocatalytic performance for the NitRR with a maximum Faradaic efficiency of ca.96%NH_(3)and the largest yield rate of ca.1.99 mg·h^(-1)·cm^(-2) at-0.5 V vs.reversible hydrogen electrode(RHE).The theoretical calculation further reveals the size effect and coordination environment on the high catalytic activity and selectivity for the NitRR.This work provides a promising various size-controlled design strategy for aerogel-based catalysts effectively applied in various electrocatalytic reactions.

Light-driven single-cell rotational adhesion frequency assay

The interaction between cell surface receptors and extracellular ligands is highly related to many physiological processes in living systems.Many techniques have been developed to measure the ligand-receptor binding kinetics at the single-cell level.However,few techniques can measure the physiologically relevant shear binding affinity over a single cell in the clinical environment.Here,we develop a new optical technique,termed single-cell rotational adhesion frequency assay(scRAFA),that mimics in vivo cell adhesion to achieve label-free determination of both homogeneous and heterogeneous binding kinetics of targeted cells at the subcellular level.Moreover,the scRAFA is also applicable to analyze the binding affinities on a single cell in native human biofluids.With its superior performance and general applicability,scRAFA is expected to find applications in study of the spatial organization of cell surface receptors and diagnosis of infectious diseases.

Opto-thermoelectric microswimmers

Inspired by the“run-and-tumble”behaviours of Escherichia coli(E.coli)cells,we develop opto-thermoelectric microswimmers.The microswimmers are based on dielectric-Au Janus particles driven by a self-sustained electrical field that arises from the asymmetric optothermal response of the particles.Upon illumination by a defocused laser beam,the Janus particles exhibit an optically generated temperature gradient along the particle surfaces,leading to an opto-thermoelectrical field that propels the particles.We further discover that the swimming direction is determined by the particle orientation.To enable navigation of the swimmers,we propose a new optomechanical approach to drive the in-plane rotation of Janus particles under a temperature-gradient-induced electrical field using a focused laser beam.Timing the rotation laser beam allows us to position the particles at any desired orientation and thus to actively control the swimming direction with high efficiency.By incorporating dark-field optical imaging and a feedback control algorithm,we achieve automated propelling and navigation of the microswimmers.Our optothermoelectric microswimmers could find applications in the study of opto-thermoelectrical coupling in dynamic colloidal systems,active matter,biomedical sensing,and targeted drug delivery.

Optothermally Assembled Nanostructures

CONSPECTUS:Nanofabrication is one of the core techniques in rapidly evolving nanoscience and nanotechnology.Conventional top-down nanofabrication approaches such as photolithography and electron beam lithography can produce high-resolution nanostructures in a robust way.However,these methods usually involve multistep processing and sophisticated instruments and have difficulty in fabricating three-dimensional complex structures of multiple materials and reconfigurability.Recently,bottom-up techniques have emerged as promising alternatives to fabricating nanostructures via the assembly of individual building blocks.In comparison to top-down lithographical methods,bottom-up assembly features the on-demand construction of superstructures with controllable configurations at single-particle resolution.The size,shape,and composition of chemically synthesized building blocks can also be precisely tailored down to the atomic scale to fabricate multimaterial architectural structures of high flexibility.Many techniques have been reported to assemble individual nanoparticles into complex structures,such as self-assembly,DNA nanotechnology,patchy colloids,and optically controlled assembly.Among them,the optically controlled assembly has the advantages of remote control,site-specific manipulation of single components,applicability to a wide range of building blocks,and arbitrary configurations of the assembled structures.In this Account,we provide a concise review of our contributions to the optical assembly of architectural materials and structures using discrete nanoparticles as the building blocks.By exploiting entropically favorable optothermal conversion and controlling optothermal−matter interactions,we have developed optothermal assembly techniques to manipulate and assemble individual nanoparticles.Our techniques can be operated both in solution and on solid substrates.First,we discuss the opto-thermoelectric assembly(OTA)of colloidal particles into superstructures by coordinating thermophoresis and interparticle depletion bonding in the solution.Localized laser heating generates a temperature gradient field,where the thermal migration of ions creates a thermoelectric field to trap charged particles.The depletion of ion species at the gap between closely positioned particles under optical heating provides strong interparticle bonding to stabilize colloidal superstructures with precisely controlled configurations and interparticle distances.Second,we discuss bubble-pen lithography(BPL)for the rapid printing of nanoparticles using an optothermal microbubble.The long-range convection flow induced by the optothermal bubble drags the colloidal particles to the substrate with a high velocity.BPL represents a general method for printing all kinds of building blocks into desired patterns in a high-resolution and high-throughput way.Third,we present the optothermally-gated photon nudging(OPN)technique,which manipulates and assembles particles on a solid substrate.Our solid-phase optical control of particles synergizes the modulation of particle−substrate interactions by optothermal effects and photon nudging of the particles by optical scattering forces.Operated on the solid surfaces without liquid media,OPN can avoid the undesired Brownian motion of nanoparticles in solutions to manipulate individual particles with high accuracy.In addition,the assembled structures can be actively reassembled into new configurations for the fabrication of tunable functional devices.Next,we discuss applications of the optothermally assembled nanostructures in surfaceenhanced Raman spectroscopy,color displays,biomolecule sensing,and fundamental research.Finally,we conclude this Account with our perspectives on the challenges,opportunities,and future directions in the development and application of optothermal assembly.

Bubble-pen lithography:Fundamentals and applications

Developing on-chip functional devices requires reliable fabrication methods with high resolution for miniaturization,desired components for enhanced performance,and high throughput for fast prototyping and mass production.Recently,laser-based bubble-pen lithography(BPL)has been developed to enable sub-micron linewidths,in situ synthesis of custom materials,and on-demand patterning for various functional components and devices.BPL exploits Marangoni convection induced by a laser-controlled microbubble to attract,accumulate,and immobilize particles,ions,and molecules onto different substrates.Recent years have witnessed tremendous progress in theory,engineering,and application of BPL,which motivated us to write this review.First,an overview of experimental demonstrations and theoretical understandings of BPL is presented.Next,we discuss the advantages of BPL and its diverse applications in quantum dot displays,biological and chemical sensing,clinical diagnosis,nanoalloy synthesis,and microrobotics.We conclude this review with our perspective on the challenges and future directions of BPL.