Aqueous Mn-ion hybrid micro-supercapacitors (AMIHMSCs) are promising systems, which can greatly improve the energy density and power density of traditional aqueous micro supercapacitors. Unfortunately, the development of AMIHMSCs has been challenging due to the low redox potential and high chemical activity of Mn metal, as well as the low capacity and poor cycle life of electrode material resulting from Mn2 + with high charge density and large solvated ion radius. Herein, we report the first generation AMIHMSCs assembled with molecular crowding electrolytes, hydroxylated Ti3C2Tx MXene (H-Ti3C2 MXene) anode and AlxV2O5 with dimethyl formamide molecules intercalation (AlVO-DMF) cathode. Benefiting from the wide electrochemical stability window and unique Mn2+ solvation structure in molecular crowding electrolytes, excellent capacitance of H-Ti3C2 MXene and enhanced structural stability of AlVO-DMF, the AMIHMSCs exhibit high energy density, power density and long cycle life. This work provides a pathway for designing high-performance AMIHMSCs.

In this work, a flexible battery structure is fabricated using soft lithography and three-dimensional (3D) printing technology. Ga _52.5 Sn _39.5 Zn _8 anode material, Bi _67 In _33 cathode material, and alkaline hydrogel electrolyte are introduced to form the flexible battery. A variety of circuit structures are fabricated to realize the series-parallel integration of different numbers of single cells and achieve the fabrication of batteries with different voltages and powers, with a maximum open-circuit voltage (OCV) of 4.6 V and a maximum output power of 1.193 mW. A reconfigurable soft battery group is proposed, and the regulation of the battery voltage has been realized through the microfluidic perfusion process without the need for an external variable-voltage circuit. We have also fabricated an EGaIn-NaOH microfluidic switch to achieve the control of the light emitting diode (LED). In addition, a wristband with a flexible battery is demonstrated to realize power supply to a liquid crystal display (LCD) with a clock or a temperature sensor.

The sluggish kinetics of charger carriers in micrometer-sized materials have spurred intense research interest of nanoscale electrode materials. However, the low volumetric capacity, severe parasitic reactions and high production-cost of nanomaterials hinder their commercial applications. Meanwhile, the exploration of micrometer-sized materials with simultaneously high gravimetric/volumetric capacity, superior rate capability and long cycle stability is still a great challenge. In this work, the performance gap between nanomaterials and micrometer-sized materials has been bridged by developing orthorhombic alpha-MoO3 microbelts with ultrathin N-doped carbon coating (MoO3@NC MB) in proton storage through the Grotthuss mechanism. The MoO3@NC MB electrode shows a record-high volumetric capacity of 412.4 mAh cm(-3), excellent rate-capability (similar to 61.5% @ 100.0 A g(-1)), and ultra-long cyclic stability (>15,000 cycles) as a result of high packing density and suppressed electrode dissolution. Detailed theoretical calculations and ex situ structure/composition investigations verify the fast proton storage in MoO3@NC MB. The fabricated MoO3@NC MB//CuFe-PBA proton full cell exhibits satisfactory energy/power densities and works efficiently in a wide temperature range of -80 degrees C to 60 degrees C (90.1% capacity retention after 10,000 cycles at -70 degrees C). This study provides valuable insight into the utilization of bulk materials for high-performance energy storage and practical applications .

In the era of artificial intelligence and big data processing, there is an urgent demand for both structurally simple and multifunctional memory devices. Although two-dimensional storage devices offer promising solutions to meet this demand, most reported devices generally face the dilemma of either single-functional or complex structures. Here, we present the Bi2O2Se/h-BN/Graphene heterostructures for optoelectronic synaptic floatinggate non-volatile memory, creating a simplified-structure device that integrates sensing, storage, and computing functions. The device exhibits a high on/off ratio exceeding 104, a memory window of 79.2 %, a retention time reaching 103 s, and a cycling lifespan of 500 cycles. It effectively emulates synaptic behaviors of photo-induced short- and long-term plasticity and paired pulse facilitation with ultralow power consumption (0.35 pJ per spike) under 365 nm stimulation. Additionally, it demonstrates a broad spectral photoresponse (365 -1050 nm). The Bi2O2Se/h-BN/Gr device enables multi-bit storage, "SELECT" photoelectric logic operations with six-valued outputs and stimulates retinal light adaptation through optoelectronic synergy. Using an artificial neural network for handwritten digit recognition, an accuracy rate of 92.24 % is achieved. This study addresses the current limitations of optoelectronic floating-gate non-volatile memory, introducing an innovative approach to integrate sensory and memory processing, thus advancing neuromorphic visual systems.

Antimony oxide (Sb2O3) exhibits a high theoretical capacity for sodium storage but suffers from poor reaction kinetics and significant volume expansion. Exposing specific crystal facets of an electrode material is considered to be an effective strategy to reduce the expansion ratio and ion diffusion barrier. Here, in situ TEM investigations and theoretical calculations indicate that the exposure of (010) facets in Sb2O3 ameliorates the expansion ratio and reduces the Na+ diffusion barrier to enhance reversible Na+ storage. Theoretical calculations also reveal that polyvinylpyrrolidone facilitates the exposure of (010) facets. A facet-engineered Sb2O3 nanobelt with exposed (010) facets (Sb2O3-(010)) demonstrates superior performance, including higher capacity, excellent rate performance, and enhanced cycling stability compared to conventional Sb2O3. Notably, at 60 °C, Sb2O3-(010) shows excellent sodium storage properties and even maintains an 80.6% capacity retention ratio after 200 cycles at 5.00 A g-1. This work underscores the potential of crystalline facet engineering to improve sodium-ion battery performance.

In this work, a novel CoP/NiCoP heterostructure with hollow nanoflower morphology is designed and constructed. Benefiting from the hollow nanoflower morphology and tuned electronic structure, the heterostructured CoP/NiCoP hollow nanoflowers are demonstrated as both high-performance supercapacitor electrode materials and superior bifunctional electrocatalysts in overall water splitting. The CoP/NiCoP delivers a high capacitance of 1476.6 F g(-1) at 1.0 A g(-1) and shows enhanced rate capability. The constructed asymmetric supercapacitor achieves a high energy density of 32.4 Wh kg(-1) at 800.5 W kg(-1) and high power density of 16.5 kW kg(-1) at 20.0 Wh kg(-1). The CoP/NiCoP hollow nanoflowers are also proven to be remarkable hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalyst which achieves the current density of 10.0 mA cm(-2) under an overpotential of 110.4 mV for HER and 310.7 mV for OER with superior stability in alkaline solution. In addition, the constructed CoP/NiCoP||CoP/NiCoP cell with CoP/NiCoP as both cathode material and anode material only requires 1.63 V @ 10.0 mA cm(-2) for overall water splitting. This study sheds lights on the rational design and construction of bimetallic phosphides for both supercapacitor and overall water splitting.

Two-dimensional van der Waals heterostructures exhibit distinctive electronic and optoelectronic properties, making them promising structures for constructing advanced multifunctional devices. However, devices based on conventional charge-carrier transport mechanisms often perform only a single function, which limits its integration and performance. Here, we present a vertical van der Waals heterostructure made of Bi2O2Se and MoTe2, allowing it to act as high-performance backward diode, forward diode, photodetector and photovoltaic device at various working conditions. The applications are enabled by band-alignment switching between p-n heterostructure controlled by minority carrier diffusion and n-n heterostructure governed by the thermionic emission and tunneling-mediated processes. As a backward diode, the device displays a high reverse rectification ratio of 5.0 x 104. As a photodetector, the device demonstrates a broad spectral photoresponse ranging from ultraviolet (365 nm) to near-infrared (1050 nm). When irradiated by 532 nm laser, the photodetector shows a responsivity of up to 11.6 A/W and achieves quick response/recovery speed of 19.6/8.8 mu s. As a photovoltaics device, an external quantum efficiency of 78% and a responsivity of 0.33 A/W are observed. This study showcases the potential for high-performance multifunctional devices utilizing Bi2O2Se/MoTe2 heterostructures and provides comprehensive insights into the designed band alignment and its applications.

Air-rechargeable batteries integrating energy harvesting, conversion, and storage provide the most portable and popular approach to self-charging power systems. However, air-rechargeable batteries are currently mostly aqueous Zn-based battery systems in which it has remained a significant challenge to solve the low discharge capacities and poor cycling stability of chemical self-charging due to continuous insertion/extraction of large-size hydrated Zn2+. Herein, efficient Bi2Te3@C cathodes with an active carbon paper substrate are developed. Further ex situ characterization analysis confirms the energy storage mechanism regarding the coexistence of H+/Zn2+ coinsertion and conversion reaction in the aqueous Zn||Bi2Te3@C battery. Benefiting from the fast dynamics process attributed to the unique mechanism, a reliable energy supply is provided even in an extended temperature range from -10 to 45 °C. More importantly, Bi2Te3@C cathodes boost the superior and repeatable air-rechargeability. A discharge capacity of up to 264.20 mA h g-1 at 0.30 A g-1 is manifested after self-charging for 11.00 h. In addition, two quasi-solid-state battery devices are connected in series to continuously power a timer. After the device is discharged and then air self-charged for just a few seconds, an LED is lit.

High-safety potassium-ion batteries (HPIBs) are highly intriguing owing to their green energy, low cost, high voltage, noncombustible, and simple assembly. However, most high-voltage HPIBs use water-in-salt electrolytes (WISE), which lead to several problems, such as a high viscosity, which significantly reduces the performance and increases the cost of HPIBs, thus impeding their development. Unfortunately, studies regarding HPIB electrolytes remain limited, further limiting the development of HPIBs. Herein, a co-solvent engineering electrolyte (4.0 m KOTf in a mixture of propylene carbonate (PC) and H2O with a volume ratio of 5.0:1.0) featuring low-cost (1/4 of WISE) and high-performance (45.43 mS cm(-1)) characteristics is proposed, which not only achieves a wide electrochemical stability window by reducing the activity of H2O, but also adjusts the solvation structure of K+. Consequently, the HPIBs assembled via co-solvent engineering electrolyte demonstrated a high energy density of 88.05 Wh kg(-1), and sufficiently operated at rates of 0.50-10.0 A g(-1) over a wide temperature range (-25-50 degrees C). This study provides a promising means for developing high-voltage HPIBs.

Aqueous zinc-ion batteries (AZIBs) are a green, low-cost and high-safety energy storage technology. Although MoS2 is a promising electrode material, low conductivity and poor stability still limit their application in AZIBs. Constructing conductive heterostructures is an effective strategy to overcome these problems. Herein, metallic 1 T-MoS2 nanosheets are innovatively combined with conductive Ti3C2 MXene, resulting in enlarged 1 T-MoS2 interlayers (from 9.5 to 9.9 angstrom) and enhanced hydrophilicity. This novel 1 T-MoS2/Ti3C2 MXene heterostructure exhibits exceptional high-rate capability (284.3 mAh/g at 0.10 A/g with 105.2 mAh/g at 10.00 A/g) and long-term cycling stability (93.2 % capacity retention after 3000 cycles). High capacity comes from the expanded ion storage space caused by the extended layer spacing of the metallic 1 T-MoS2. Outstanding rate capability thanks to ultrafast electrons and ions transport from Ti3C2 MXene. Prominent long-term cycling stability is attributed to the efficient synergistic effect of 1 T-MoS2 and Ti3C2 MXene in the 3D interconnected networks. As a proof of concept, the wearable quasi-solid-state Zn-ion battery employing the 1 T-MoS2/Ti3C2 MXene cathode exhibits stable electrochemical performance under different bending conditions. This work explores a new route to design high-performance layered cathode materials for AZIBs.

High-performance self-powered pressure sensors have attracted much attention due to their potential applications in bionic limbs, healthy motion detection, medical devices, and other fields. However, existing devices are either imperceptible to the pressure direction or require an external power source as a driving force. Here, a pressure sensor inspired by the structure of serosal membranes is reported, which contains a novel partially reduced graphene oxide (prGO) membrane. In this Serosa-Mimetic structured membrane, a narrow "Trail" structure containing -COON is considered as an ion filter and ion conductor, which facilitates the directional migration of cations under external stimuli, resulting in a directional flow of net charges, resulting in current (or voltage) signal. Therefore, the prGO-Trail membrane can be used as an ion transport layer to facilitate self-powered pressure sensing. This pressure-driven output voltage (and current), produced by ion selectivity, is linear with the applied pressure. The fabricated self-powered bionic pressure sensor has good performance, the optimized response sensitivity is 0.282 nA Pa-1, the response/recovery time is 90/110 ms, and long-term stability (1000 cycles), which provides a meaningful design idea and a larger open field of vision for the next generation of self-driving bionic pressure sensors.

Protons (H+) are considered as ideal charge carries for rechargeable batteries because of the small size, high ionic mobility and wide availability. In this work, MoO3 nanobelts with rich defects are prepared by simple hydrothermal treatment of MoO3 nanoparticles and are demonstrated as high-performance electrode materials for proton battery. Benefiting from the nanobelt morphology, abundant oxygen vacancy, large interlayer spacing, improved conductivity and fast ion transfer, the MoO3 nanobelts electrode delivers a state-of-the-art capacity of 285.3 mAh g- 1 at the current density of 1.0 A g- 1, and -75% of the initial capacity is retained at 50.0 A g- 1. It is found that the MoO3 nanobelts electrode can still maintain its original capacity, nanobelt morphology and crystal structure even after 23,000 cycles. Notably, the electrode delivers a high areal capacity of 3.48 mAh cm-2 at a high mass loading of 16.0 mg cm- 2. The proton battery assembled with MoO3 nanobelts anode and N-doped active carbon cathode shows the maximum energy density of 46.2 Wh kg- 1 at the power density of 800.3 W kg- 1. The proton battery shows satisfactory proton storage properties at a wide temperature range of -25 degrees C 65 degrees C. This study provides insights into the design of ultrafast and wide-temperature proton battery for practical applications.

The exploration for pseudocapacitive materials that employ surface Faradaic reactions to store charges in supercapacitors is highly desirable. However, the traditional transition metal oxides with poor electronic conductivity and sluggish reaction kinetics lead to a poor rate capability. In this study, a Co(PO3)2/Cu3P heterostructure is fabricated by a facile in situ phosphorization process. Benefiting from the formation of heterojunctions and modified electronic structures, the electronic transfer and ionic diffusion kinetics have been significantly improved. Specifically, the Co(PO3)2/Cu3P heterostructure electrode exhibits a capacitance of 787.1 F g-1 at 1.0 A g-1 and a superior rate capability of 78.4% capacitance retention at 20.0 A g-1. The fabricated Co(PO3)2/Cu3P//AC asymmetric supercapacitor device with this Co(PO3)2/Cu3P heterostructure as the positive electrode shows an excellent energy density of 39.8 Wh kg-1 at a power density of 936.7 W kg-1 and satisfactory cyclic stability. This design of a metaphosphate based heterostructure provides a path to explore electrode materials with both high capacitance and superior rate capability.

Replacing Zn metal with intercalated materials as the aqueous zinc-ion batteries (AZIBs) anode is an ef-fective strategy to solve serious zinc dendrites problem. MXene-based derived materials combine the ad-vantages of both derivatives with excellent electrochemical activity and MXene with high electrical conductivity. Here, we report an in situ derived strategy for synthesizing H2Ti3O7-MXene from common Ti3C2 MXene by one-step hydrothermal process with simultaneous alkalization and oxidation, followed by ion-exchange reaction. It is experimentally verified that H2Ti3O7 -MXene exhibits an extremely low char-ging voltage of only 0.25 V, which has a satisfactory potential for AZIBs anodes. Through characterization analyses, H2Ti3O7-MXene nanoflowers consist of countless connectively interlaced and entangled nanor-ibbons, which shorten the ion diffusion path and accelerate Zn2+ diffusion kinetics. The synergistic effect between H2Ti3O7 and MXene enables H2Ti3O7-MXene to achieve efficient and reversible Zn2+ (de)inter-calation. Specifically, at 0.10 A g-1, the specific capacity of 61.20 mAh g-1 is achieved and no significant discharge specific capacity decline occurs at 0.60-2.00 A g-1. The assembled zinc ion full-cell (ZnxMnO2// H2Ti3O7-MXene) shows the excellent cyclic stability and good coulombic efficiency during 600 GCD cycles. This work proves the feasibility of MXene-based derivatives for AZIBs anode and sheds light on developing efficient intercalated MXene derived anodes.(c) 2023 Elsevier B.V. All rights reserved.

Van der Waals semiconductors have been really confirmed in two-dimensional (2D) layered systems beyond the traditional limits of lattice-matching requirements. The extension of this concept to the 1D atomic level may generate intriguing physical functionalities due to its non-covalent bonding surface. However, whether the curvature of the lattice in such rolled-up structures affects their optoelectronic features or the performance of devices established on them remains an open question. Here, MoS2-based nanoscrolls were obtained by virtue of an alkaline solution-assisted method and the 0D/1D (BaTiO3/MoS2) strategy to tune their optoelectronic properties and improve the light sensing performance was explored. The capillary force generated by a drop of NaHCO3 solution could drive the delamination of nanosheets from the underlying substrate and a spontaneous rolling-up process. The package of BaTiO3 particles in MoS2 nanoscrolls has been evident by TEM image, and the optical characterizations were mirrored via micro-Raman spectroscopy and photoluminescence. These bare MoS2 nanoscrolls reveal a reduced photoresponse compared to the plane structures due to the curvature of the lattice. However, such BaTiO3/MoS2 nanoscrolls exhibit a significantly improved photodetection (Rhybrid = 73.9 A/W vs Ronly = 1.1 A/W and R2D = 1.5 A/W at 470 nm, 0.58 mW·cm-2), potentially due to the carrier extraction/injection occurring between BaTiO3 and MoS2. This study thereby provides an insight into 1D van der Waals material community and demonstrates a general approach to fabricate high-performance 1D van der Waals optoelectronic devices.

The polymorphs and the phase transformation process of two-dimensional (2D) oxide materials, which are the crucial building blocks of high-performance nanodevices, are rarely studied. Here, we directly observed the atomic structural evolution of anatase-to-rutile phase transformation of TiO2 nanosheets using the in situ heating transmission electron microscopy (TEM) technique. The transformation process of the [010] direction and the (013) plane of anatase to [1 $(1) over bar $0] and (11 $$(1) over bar) of rutile was captured by electron diffraction. The phase transformation was highly affected by the as-prepared nanosheet surface structure by the templating effect. In addition, the dependence of crystallographic orientation with respect to electron beam irradiation was also revealed. Through a different path, the [010] direction and the (004) plane of anatase were transformed to [1 $(1) over bar $0] and (11 $$(1) over bar) of rutile with nucleation from the edge of the sheet by high-resolution TEM characterization, which had a high electron dose rate. The electron energy loss spectrum (EELS) obtained at different temperatures suggested the reduced valence of Ti, which was possibly due to the formation of oxygen vacancies. This finding could shed light on the unique structure transformation behavior of 2D oxides and the effective control of their polymorph nanostructures by both temperature and electron irradiation, which could facilitate the discovery of new functionalities.

Non‐contact humidity sensors have been widely explored as human–computer interaction for the internet of things and artificial intelligence. However, except for the existing sensing mechanisms, such as resistive, capacitive, and functional groups gradient based device, little attention has been paid to exploiting new sensing mechanisms with novel properties which can meet the requirements of miniaturization and integration. Here, a self‐powered potentiometric humidity‐transduction mechanism, which modulates the measured potential difference between two electrodes by humidity stimulation on the graphene oxide (GO) solid electrolyte, is reported. On the strength of this mechanism, a highly adjustable potentiometric humidity sensor with sandwich structure of reduced graphene oxide/GO/foamed metal (nickel, zinc, iron and copper), exhibiting good scalability and cost‐efficiency, enabling fast response/recovery (0.8 s/2.4 s), ultra‐high response (0.77 V) and excellent stability (over 1500 cycles) is developed. Unlike traditional sensing mechanisms, the manipulation mechanism raised here shows self‐powered ability with no need for an additional power unit and has ultra‐low power consumption. These results provide a new scheme for the research and development of self‐powered humidity sensors, and these sensors show superior performance in non‐contact sensing applications.

The fields of electronic skin, man-machine interaction, and health monitoring require flexible pressure sensors with great sensitivity. However, most microstructure designs utilized to fabricate high-performance pressure sensors require complex preparation processes. Here, MXene/polyaniline (PANI) foam with 3D porous structure is achieved by using a steam-induced foaming method. Based on the structure, a flexible piezoresistive sensor is fabricated. It exhibits high sensitivity (690.91 kPa-1 ), rapid response, and recovery times (106/95 ms) and outstanding fatigue resistance properties (10 000 cycles). The MXene/PANI foam-based pressure sensor can swiftly detect minor pressure and be further used for human activity and health monitoring.

Rechargeable zinc-based aqueous system is attractive for energy storage technology due to its safety, low cost, and ecological friendliness. However, the growth of Zn dendrites in anode severely limits the development of the energy storage system. Here, TiSe2 is verified as an intercalated anode for aqueous zinc ion batteries (ZIBs) and zinc ion hybrid supercapacitors (ZHSCs) by a series of experimental and theoretical studies. The interlayer spacing of 0.601 nm makes TiSe2 suitable for (de)intercalation of zinc ions and its good electronic conductivity endows TiSe2 with excellent electrical charge transport characteristics. The TiSe2 electrode shows a capacity of 128.0 mA h g(-1) at 0.20 A g(-1), low working potential window (0.00-0.60 V vs Zn-2}/Zn), and a recyclability of 70.0% retention after 300 cycles. Fabricated by TiSe2 anode and VO2 cathode, an aqueous ZIBs is successfully demonstrated, delivering a capacity of 44.3 mA h g(-1) at 0.20 A g(-1). Fabricated by TiSe2 anode and activated carbon (AC) cathode, a ZHSC is demonstrated with a specific capacitance of 60.6 F g(-1) at 0.20 A g(-1). This work brings an attempt and exploration of electrode materials about a (de)intercalation battery-type anode instead of Zn metal anode for aqueous ZIBs and ZHSCs.

Two-dimensional titanium carbide (MXene) has attracted significant attentions in supercapacitors owing to its high metallic conductivity and excellent chemical properties. However, the inherent restacking issue and -F surface termination severely limit the energy storage. Here, an effective strategy to construct high-performance Ti3C2Tx MXene (A-Ti3C2Tx /PANI) based on the synergistic effect of modified surface termination, expanded interlayer spacing and three-dimensional structure is reported. Benefiting from the interconnected structure, enhanced electrochemical activity and efficient ion/electron transport layer, the prepared negative electrode demonstrates an outstanding specific capacitance of 652.3 F g(-1) at 1 A g(-1) (similar to 3 times of the pristine MXene), an impressive rate capability with 81% capacitance retention at 50 A g(-1), and excellent cycling stability with above 99% capacitance retention after 10, 000 cycles. In addition, a symmetric supercapacitor is fabricated using A-Ti3C2Tx/PANI, and it delivers a high energy density of 20.3 Wh kg(-1). Furthermore, the prepared free-stranding film electrode based on A-Ti3C2Tx /PANI shows a high volumetric capacitance of 2368 F cm(-3). The improved gravimetric and volumetric capacitances surpass almost all the reported MXene-based electrodes. This study demonstrates a new strategy to enhance the electrochemical performance of Ti3C2Tx electrode and could be a universal way applicable to other MXenes.