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Sustainable organic materials have gained considerable attention as electrodes for zinc-ion batteries (ZIB) due to their high theoretical capacity, structural versatility, and environmental friendliness. However, issues of inferior capacities and poor rate performance owing to limited inherent electronic conductivity and severe dissolution still persist. Herein, sandwich-structured perylene diimide-ethylene diamine/graphene (PDI-EDA/EG) composites are judiciously designed and synthesized. The two-dimensional graphene host can interact with the PDI-EDA polymer through π–π stacking, endowing accelerated ion/electron transfer, abundant active sites, excellent structural integrity, and mitigated solubility of the hybrid electrodes. When evaluated as an anode in ZIB, the hybrid electrode delivers a high capacity (110.2 mAh g−1 at 0.1 A g−1), superior rate capability (88.9 mAh g−1 at 5 A g−1), and exceptional durability (93.4% capacity retained after 1000 cycles). The structure evolution of the hybrid electrode during the insertion/extraction cycle was investigated by ex-situ Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS), revealing the reversible Zn2+ storage at carbonyl sites. In addition, a prototype rocking-chair ZIB cell was constructed with a zinc pre-intercalated MnO2 cathode, displaying an ultrahigh energy density of 54.9 Wh kg−1 at a power density of 42.5 W kg−1 and excellent stability with negligible capacity decay after 1000 cycles.

Reversible electrochemical mirror (REM) electrochromic devices based on reversible metal electrodeposition are exciting alternatives compared with conventional electrochromic because they offer electrochemical tunability in multiple optical states, long durability, and high contrast. Different from conventional electrochromic materials, of which the color change depends on the intercalation/deintercalation of ions into electrochromic films, the change in the optical states of REMs is based on the reversible electrodeposition and dissolution of metal. In this study, a REM electrochromic device with a Cu hybrid electrolyte composed of aqueous and nonaqueous components is proposed, which serves as an electrolyte reservoir that hosts Cu ions for reversible electrodeposition/dissolution. The hybrid electrolyte promotes the electrochemical reversibility of the Cu redox, an enhanced electrochromic performance, and a robust cycling stability of 5000 cycles (minor degradation of 4.71%). The investigation of the discharging/charging of the Cu hybrid REM device reveals that the Cl-/ClO- redox mechanism occurs at the cathode. Finally, an unprecedented dual-functional Cu hybrid REM energy storage device has been realized. National Research Foundation (NRF) Published version This research was supported by the National Research Foundation, the Prime Minister’s Office, Singapore, under its Campus for Research Excellence and Technological Enterprise (CREATE) program.

The rational design and scalable assembly of nanoarchitectures are important to deliver highly uniform, functional films with high performance. However, fabrication of large-area and high-performance films is quite difficult because of the challenges in controlling homogeneous microstructures, interface properties, and the high cost of the conventional vacuum deposition technique. Here, we report a solution-processed molecular level assembly approach to fabricate self-supported (without any binders or conductive additives) large-area (up to 810 cm ) functional films with controllable thickness and high homogeneity. We show that the assembled prototypical Fe(II)-based metallo-supramolecular polymer (polyFe) film exhibits unprecedented electrochromic performance such as ultrahigh coloration efficiency (750.3 cm C ), fast switching speed (

Formation of ionogels through in situ polymerization can effectively improve electrolyte processability; however, the curing process has been slow and oxygen-sensitive. Considering the low oxygen solubility of poly(ionic liquid)s (PILs), in situ polymerized ionogels are designed to realize excellent electrolytes. Herein, two in situ polymerized ionogels (PIL A & PIL B) are formulated, and they can be rapidly photocured within a minute. The ionogels are highly transparent, stretchable, and exhibit excellent physicochemical stability, including thermal, electrochemical, and air stability, allowing them to perform in various conditions. Benefitting from these properties, two high-performance electrochromic devices (ECDs) are assembled, with iron-centered coordination polymer (FeCP) and tungsten oxide (P-WO3 ) electrochromic materials, achieving high color contrast (45.2% and 56.4%), fast response time (1.5/1.9 and 1.7/6.4 s), and excellent cycling endurance (>90% retention over 3000 cycles). Attributed to the thermal robustness of the ionogels, the ECDs can also be operated over a wide temperature range (-20 to 100 °C). With the use of deformable substrates (e.g., ultrathin ITO glass), curved electrochromic eye protector and flexible electrochromic displays are realized, highlighting their potential use in futuristic wearables. Ministry of Education (MOE) Nanyang Technological University National Research Foundation (NRF) W.C.P. is supported by NTU Research Scholarship awarded by Nanyang Technological University. The authors acknowledge the funding from Ministry of Education AcRF Tier 1 RG64/21, and Campus for Research Excellence and Technological Enterprise (CREATE) that is supported by the National Research Foundation, Prime Minister’s Office, Singapore.

An electrochromic device (ECD), which can switch between black and transmissive states under electrical bias, is a promising candidate for smart windows due to its color neutrality and excellent durability. Most of the black ECDs are achieved through a reversible electrodeposition and dissolution mechanism; however, they typically suffer from relatively poor cycling stability and a slow coloration/bleaching time. Herein, we present a heat-insulating black ECD with a gel electrolyte that operates via reversible Ni-Cu electrodeposition and dissolution. With the adoption of a Cu alloying strategy and a compatible gel electrolyte, this two-electrode ECD (5.0 cm × 2.5 cm) can achieve a cycling stability of 1500 cycles with transmittance modulation up to 55.2% in short coloration (6.2 s) and bleaching times (13.2 s) at a wavelength of 550 nm. Additionally, the ECD can be switched from the transparent state (visible light transmittance: 0.566) to the opaque state (visible light transmittance: 0.003) within 1 min, reaching transmittance less than 5% across the visible-near-infrared spectrum (400-2000 nm) to efficiently block solar heat. Besides, in the voltage-off state, the black Ni-Cu alloy film can be sustained for more than 60 min (at room temperature, λ = 550 nm). Under infrared irradiation (170 W/m2) for 30 min, the black ECD blocks up to 35.0% of infrared radiation, which not only effectively prevents the heat transmission for energy management but also finds potential applications for promoting indoor human health and indoor farming. Ministry of Education (MOE) National Research Foundation (NRF) This work was funded by the Ministry of Education AcRF Tier 1 (2021-T1-002-115) and the Campus for Research Excellent and Technological Enterprise (CREATE), National Research Foundation, Singapore.

The similarity in electrochemical mechanisms in electrochromic and energy storage devices has inspired explorations of dual-functional devices. However, complementary dual-functional devices often neglect charge balance and suffer from unsatisfactory capacity. Here, electrochemically deposited NiO was balanced by Zn anode, constructing an electrochromic Zn battery (EZB) in both aqueous mild (ZnCl2) and alkaline (KOH) electrolytes. With well-adjusted electrochemical deposition condition, nanoporous instead of dense NiO film was obtained, manifesting faster switching for electrochromism and higher capacity for charge storage. In addition, the alkaline EZB outperforms the mild counterpart, due to the formation of larger content of Ni3+ species upon oxidation. The alkaline EZB harvests areal capacity of 20 mAh/m2 at 0.02 mA/cm2 and high-rate performance (17.1 mAh/m2 at 0.2 mA/cm2) for energy storage, while achieving optical contrast of 36%, high transmittance at clear state (>90%), fast switching time (tb = 5.3s, tc = 1.9s), and excellent switching stability (no contrast degradation after 2000 cycles) for electrochromism. A 5∗5 cm2 charged alkaline NiO//Zn EZB can power a timer for more than 30 min, accompanied by a gradual bleaching process, demonstrating the outstanding dual functionalities. This work presents the construction of excellent dual-functional EZB. Ministry of Education (MOE) National Research Foundation (NRF) The authors acknowledge the funding support by the National Research Foundation, Prime Minister's Office, Singapore, under its Campus for Research Excellence and Technological Enterprise (CREATE) program, and Ministry of Education, AcRF Tier 1, Award No. RG64/21.

Present challenges in electrochromic devices include the limited transmissive and reflective inter‐switchability, while achieving high optical contrast, fast switching speed, and cycling stability, simultaneously. In article number 1903198, Pooi See Lee and co‐workers develop a quasi‐solid‐state tristate reversible electrochemical mirror device, which offers highly reversible switching between transparent, greyish‐blue, and mirror (reflective) optical states. The alloying approach facilitates the electrodeposition and dissolution of Cu mirror film, allowing enhanced device stability. [Image: see text]

Reversible electrochemical mirror (REM) electrochromic devices with electrochemical tunability in multiple optical states are exciting alternatives to conventional electrochromic smart windows. Electrochromic devices are studied extensively, yet widespread adoptions have not been achieved due to problems associated with durability, switching speed, limited options on optical states, and cost. In this study, a REM electrochromic device based on CuSn alloy is developed, which offers highly reversible switching between transparent, greyish‐blue, and mirror states via reversible electrodeposition and dissolution. The alloying element, Sn acts as an electrochemical mediator, which facilitates the electrodeposition and dissolution of Cu. The CuSn‐based REM device shows superior cycling stability for 2400 cycles (transmittance mode) and 1000 cycles (reflectance mode). The electrodeposited CuSn alloy film is resistant to surface oxidation in ambient air, with a 2.9% difference in reflectance at 2000 nm after 3 days. In addition, the alloy film exhibits excellent NIR reflectance property with thermal modulation of 18.5 °C at a high temperature of 180 °C. The REM device with zero power consumption maintains its mirror state for at least 100 min, making it a promising candidate for energy‐efficient applications., The quasi‐solid‐state tristate reversible electrochemical mirror (REM) device offers highly reversible switching between transparent, greyish‐blue, and mirror states via reversible electrodeposition and dissolution. The REM shows superior thermal barrier property compared to the bare substrate. The extended memory effect of the REM device is achieved in the presence of quasi‐solid‐state polymer electrolyte.

The emergence of soft energy devices provides new possibilities for various applications, it also creates significant challenges in the selection of structural design and material compatibility. Herein, we demonstrate a stretchable transmissive electrochromic energy storage device by inkjet-printing single layer of WO3 nanoparticles on an elastomeric transparent conductor. Such hybrid electrode is highly conductive and deformable, making it an excellent candidate for the application: large optical modulation of 40%, fast switching speed (

High-quality patterns were successfully prepared by inkjet-printing WO3-PEDOT:PSS composites on different substrates including the rigid FTO glass and most importantly, on flexible PEDOT:PSS/Ag grid/PET. Excellent electrochromic performances can be achieved, including large optical modulation (85.7% optical contrast at the wavelength of 633 nm on FTO glass substrate), fast switching speed (coloration/bleaching time of 2.4/0.8 s on the PEDOT:PSS/Ag grid/PET substrate), instantaneous coloration efficiency (68.8 cm2 C−1) and good cycling stability (up to 10,000 cycles). The effects of the applied potential window during electrochemical evaluation on the electrochromic performances were analyzed in detail. The printed electrochromics films on PEDOT:PSS/Ag grid/PET showed the best electrochemical stability, in agreement with its superior conductivity and transmittance at 633 nm of 0.6 Ω/sq and 66%, respectively. It sustained transmittance modulation of about 75.5% and 53.1% of its first cycle recorded contrast at 633 nm, after being subjected to 1000 and 5000 cycles, respectively, and maintained good electrochemical stability up to 10,000 cycles. Moreover, a robust mechanical stability was also achieved by the printed films on flexible PEDOT:PSS/Ag grid/PET substrate. The film maintained a transmittance modulation of 85.8% of its original contrast after 5000 bending cycles at a curvature radius of 1 cm. The inkjet-printed WO3 nanocomposite based flexible electrochromic displays exhibited excellent electrochromic performance, making it a promising candidate for energy efficient displays, e-books, e-cards and multifunctional electronic devices. NRF (Natl Research Foundation, S’pore)

Ultrathin tungsten molybdenum oxide nanoparticle films were fabricated from aqueous ink by a spray coating technique. With the in situ heating of the hot plate during the spray coating process, the detrimental effects of oxygen vacancies on electrochromic (EC) materials could be eliminated. The spray coated ultrathin films exhibit higher contrast than the drop casted films, which would provide a versatile and promising platform for energy-saving smart (ESS) windows, batteries, and other applications.

Some animals and plants in nature are endowed with elegant color-changing ability, which inspired the developments of biomimetic systems with multifunctionality, such as controllable colors, transmittance, and mechanical pliability that are significant for the development of energy-efficient and deformable chromic devices, such as wearable displays, smart windows, decorative architectures, camouflage devices, etc. Inspired by the color-changing ability of diphylleia grayi (commonly known as skeleton flower), we developed a porous PDMS film that dynamically and dramatically changes its color by the adsorption/desorption of minute amount of water (5 g m-2) or other solvents. This hydrochromic phenomenon was analyzed in detail and it matched well with the Mie scattering theory. The porous PDMS film of about 0.4 mm thick exhibits a large optical modulation (about 75~80%) in the broad visible and near infrared region and coloration speed of less than 9 mins. Additionally, the PDMS film can sustain uniaxial strain up to 100% at both transparent and colored states. We believe this new strategy to develop highly scalable porous PDMS film offers a practical route to realize bionic and botanic inspired deformable energy-efficient façade, chromogenic wearables, smart window, smart display, and camouflage etc. NRF (Natl Research Foundation, S’pore) Accepted version

In this paper, uniform NiO nanoparticles on different substrates were successfully synthesized by a simple and low-cost solvothermal method. The high capacitance (1386 F g−1 at 1 A g−1) and excellent rate capability were achieved for NiO nanoparticle film as supercapacitor electrode. A large optical modulation (63.6% at 550 nm), high coloration efficiency (42.8 cm2 C−1 at 550 nm) and good cycling stability can be achieved when the same NiO nanoparticles are used for electrochromic application. The excellent electrochemical performance is attributed to the uniform nanoparticles morphology and stable chemical bonding of the NiO nanoparticle on the substrates, which shorten the ion diffusion length and greatly facilitated the charge transfer both at the contact interfaces and within the electrode materials during the electrochemical process. In addition, we present a smart supercapacitor which function as a regular energy storage device and simultaneously monitor the level stored energy by visual changes. The findings present great promise for NiO nanoparticle film as practical electrode materials as chromo-supercapacitor.

Electrochromic (EC) technology has progressed tremendously in recent years. Rigid EC devices have advanced to offer additional attractive physical attributes such as flexibility, stretchability, and foldability. These features are appealing for wearable and futuristic technologies, and hence serve to revolutionize EC applications toward deformable electronics. In this review, the essential prerequisites of each component of the flexible EC devices are delineated, such that each component is mechanically flexible to maintain the structural integrity of the device. The recent progress in flexible EC performance is discussed, from flexible to stretchable and the foldable device being the latest trend in deformable electronics. Next, we address the pertinent challenges often encountered in the fabrication of flexible EC devices and outline the adopted strategies from the literature to this point. Finally, the concept of the multifunctional EC device is discussed for achieving versatile emerging applications. We envision that this review will shed light on the properties of flexible ECs and shape the new milestones to be set for realizing a more versatile multifunctional EC device. NRF (Natl Research Foundation, S’pore)

Reversible electrochemical mirror (REM) device can be electrochemically tuned to exhibit dual transmittance and reflectance modulations in a single device. Conventional REM devices reversibly switched between transparent and mirror states. However, it is of great challenge to maintain the mirror state of the REM devices due to the diffusion of anions into the metallic film at the open-circuit state. In this work, we report a Cu-based REM device which offers reversible switching between transparent, blue and mirror states with judicious selection of electrolyte and controllable electrodeposition. The blue state can be obtained through the formation of copper (I) chloride, CuCl, when copper (II) chloride CuCl2 undergoes electrochemical reduction. The polymer host, PVA (poly(vinyl alcohol)) plays an important role in reducing the surface roughness of the electrodeposited mirror film, improving film uniformity and sustaining the mirror state of the device during the voltage-off state. NRF (Natl Research Foundation, S’pore) Accepted version

An extremely stretchable electroluminescent device is fabricated by P. S. Lee and co-workers, as described on page 4490. The stretchable alternating-current electroluminescent (ACEL) device possesses extremely high stretchability, and can be linearly stretched to 700% with the luminance being maintained at 70% of the initial value before stretching. The device can be repeatedly stretched to 400% with stable emission behavior. The presented device will provide new opportunities in stretchable lighting, volumetric 3D displays, interactive readout systems, and other unprecedented applications.

Lycopene extraction was carried out via the ultrasonic assisted extraction (UAE) with response surface methodology (RSM). Sonication enhanced the efficiency of relative lycopene yield (enhancement of 26% extraction yield of lycopene in 6 replications at 40.0 min, 40.0 °C and 70.0% v/w in the presence of ultrasound), lowered the extraction temperature and shortened the total extraction time. The extraction was applied with the addition of oxygen-free nitrogen flow and change of water route during water bath sonication. The highest relative yield of lycopene obtained was 100% at 45.0 °C with total extraction time of 50.0 min (30:10:10) and ratio of solvent to freeze-dried tomato sample (v/w) of 80.0:1. Optimisation of the lycopene extraction had been performed, giving the average relative lycopene yield of 99% at 45.6 min, 47.6 °C and ratio of solvent to freeze-dried tomato sample (v/w) of 74.4:1. From the optimised model, the average yield of all-trans lycopene obtained was 5.11 ± 0.27 mg/g dry weight. The all-trans lycopene obtained from the high-performance liquid chromatography (HPLC) chromatograms was 96.81 ± 0.81% with 3.19 ± 0.81% of cis-lycopenes. The purity of total-lycopene obtained was 98.27 ± 0.52% with β-carotene constituted 1.73 ± 0.52% of the extract. The current improved, UAE of lycopene from tomatoes with the aid of RSM also enhanced the extraction yield of trans-lycopene by 75.93% compared to optimised conventional method of extraction. Hence, the current, improved UAE of lycopene promotes the extraction yield of lycopene and at the same time, minimises the degradation and isomerisation of lycopene.

Porous WO

Porous WO3 films with ultra-high transmittance modulation were successfully fabricated on different substrates by a novel, facile and economical pulsed electrochemical deposited method with 1.1 s interval time between each pulse. The near ideal optical modulation (97.7% at 633 nm), fast switching speed (6 and 2.7 s), high coloration efficiency (118.3 cm2 C−1), and excellent cycling stability are achieved by the porous WO3 on ITO-coated glass. The outstanding electrochromic performances of the porous WO3 film were mainly attributed to the porous structure, which facilitates the charge-transfer, promotes the electrolyte infiltration and alleviates the expansion of the WO3 during H+ insertion compared to that of the compact structure. In addition, the relationships between the structural and electrochemical activity of the electrochromic WO3 films were further explored by the scanning electrochemical microscopy. These results testify that the porous structure can promote the infiltration of electrolyte and reduce the diffusion path, which consequently enhance the electrochemical activity. ASTAR (Agency for Sci., Tech. and Research, S’pore) Published version

Fenestration, such as windows, plays a key role in modern architecture as it has enormous impact on the energy efficiency and comfort to the occupants of the building. Herein, current state‐of‐art strategies of nanostructured electrochromic materials, the fabrication of large scale smart windows, rational design of multifunctional smart chromogenic devices, and their performance are highlighted. Moreover, the current challenges from material selection to smart window performance are discussed and feasible solutions are provided. Development of a novel, simple, and economical synthesis of electrochromic materials is the first step in realizing high‐performance smart window. In addition, electrolyte, packaging materials, and judicious design of the fabrication process also play critical roles in the development of multifunctional and energy‐efficient smart windows. Finally, the concept of energy‐efficient multifunctional smart windows is addressed in which the smart windows are powered by sustainable energy in daytime, while the windows dynamically control the solar radiation into the building through transmittance modulation, enabling adjustable occupant's privacy. Sustainable energy can be stored in the smart windows during daytime and can be discharged to power other electronic devices at night. It is envisioned that this review shall promote a rapid development on electrochromic materials and novel multifunctional smart windows. NRF (Natl Research Foundation, S’pore) Accepted version