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Portable sensor technologies are indispensable in personalized healthcare and environmental monitoring as they enable the continuous tracking of key analytes. Human sweat contains valuable physiological information, and previously developed noninvasive sweat-based sensors have effectively monitored single or multiple biomarkers. By successfully detecting biochemicals in sweat, portable sensors could also significantly broaden their application scope, encompassing non-biological fluids commonly encountered in daily life, such as mineral water. However, developing a portable electrochemical sensing system with sustainable power remains a challenge for real-time, on-site analysis in complex outdoor applications. Here, we present a power-sustainable and portable electrochemical sensing platform, composed of multiple electrochemical sensors, a multichannel data acquisition circuit, a microfluidic module, and a power supply module, that is designed to conform onto the human body for daily use. The device enables simultaneous and selective measurement of Na+, K+, and pH levels in sweat and outdoor environments wirelessly. Additionally, we utilize a dual power supply module composed of a lithium-ion battery and a solar cell, offering a sustainable power supply for various application scenarios. Looking forward, this novel platform can serve as a bridge between monitoring biological fluids and detecting nonbiological fluids in complex outdoor environments.

Manganese-based NASICON-type compounds are promising as high-energy-density cathodes for sodium-ion batteries. However, the structural defects of Mn ions inside the crystal framework reduce the sodium storage capacity, voltage plateau, and cyclic stability of the cathodes. Here, a strategy to inhibit the Mn ion defects of Na4MnCr(PO4)3has been proposed by using different phosphate sources. It is found that Na4MnCr(PO4)3prepared with NH4H2PO4(NMCP-N) exhibits less noticeable voltage hysteresis than that of Na4MnCr(PO4)3prepared with H3PO4(NMCP-H), indicating that the site occupation defects of Mn ions in the Na4MnCr(PO4)3crystal structure are successfully suppressed, as confirmed by theoretical calculations and structural refinements. In the case of NMCP-N, a capacity of 109.7 mAh g–1is delivered at 0.01 A g–1, and 54.2% capacity retention can be kept after 500 cycles at 0.5 A g–1, which is much better than that of the counterpart of NMCP-H (a lower capacity of 96.1 mAh g–1and poorer cyclability of only 22.8% capacity retention after 500 cycles), showing that the structure defects strongly affect the sodium storage properties of Na4MnCr(PO4)3cathodes. This work provides an effective strategy to manipulate the structure defects of Mn-based NASICON-type cathode materials to enhance their electrochemistry.

Zn metal with high specific capacity and low redox potential is deemed to be an ideal anode material for aqueous zinc-ion batteries (ZIBs). However, the serious dendrite problems induced by the uneven deposition of zinc shorten the service life and hinder the development of ZIBs. According to the nucleation and growth mechanism, the charge distribution at the anode interface is the critical factor affecting the deposition morphology. Herein, CF4plasma technology is applied for the first time to in situ modification of the Zn anode, and then, the uniform nanoscale ZnF2particles are formed. Due to the excellent ionic conductivity and poor electronic conductivity of ZnF2, the ion and electron distribution at the anode interface is orderly regulated, thus guiding uniform and reversible deposition behavior and restraining the dendrite growth. As a result, the Zn@ZnF2-5 anode exhibits low nucleation overpotential (16 mV), long cycle life (2500 h at 1 mA cm–2and 1 mA h cm–2), and excellent resistance to high current density (20 mA cm–2) and high discharge depth (16%). Meanwhile, the Zn@ZnF2-5|I2@AC full battery shows remarkable cycle stability (1000 cycles) with ∼10% discharge depth of the anode. The novel and practical CF4plasma in situ modification strategy provides a new idea for the interface modification of zinc anode.

Ferroelectric lead-free KxNa1–xNbO3(KNN) perovskite, whose piezoelectric properties can be comparable to those of traditional Pb-based systems, has aroused wide concern in recent years. However, the specific influences of the stress field on KNN’s structure and piezoelectric properties have not been well clarified and there are few descriptions about the temperature–pressure phase diagram. Here, we analyzed the phonon mode behavior and structural evolution of K0.5Na0.5NbO3-0.05LiNbO3(KNN-LN) and MnO2-doped single crystals with pressure- and temperature-dependent phase structure variations by theoretical calculation, polarized Raman scattering, and infrared reflectance spectra. The different phase structures can be predicted at high pressure using the CALYPSO method with its same-name code. The rhombohedral → orthorhombic → tetragonal → cubic phase transition process can be discovered in detail by Raman spectra under different temperatures and pressures. The phase coexistence on the thermal phase boundary was confirmed by basic anastomosis. Meanwhile, it was found that the substitution of Mn in the NbO6octahedron aggravates the deformation of high pressure on KNN-LN and the substitution of Mn at the B-site intensifies the structural evolution more severely than at the A-site. The present study aims at exploring octahedra tilt, phonon vibrations, and the internal structure on the general critical phase boundary in KNN-LN crystals. It provides effective help for the study of lead-free perovskite phase transformation and the improvement in piezoelectric properties under a high-pressure field.

Flexible memory and wearable electronics represent an emerging technology, thanks to their reliability, compatibility, and superior performance. Here, an Sb2TexSe3–x(STSe) phase change material was grown on flexible mica, which not only exhibited superior nature in thermal stability for phase change memory application but also revealed novel function performance in wearable electronics, thanks to its excellent mechanical reliability and endurance. The thermal stability of Sb2Te3was improved obviously with the crystallization temperature elevated 60 K after Se doping, for the enhanced charge localization and stronger bonding energy, which was validated by the Vienna ab initiosimulation package calculations. Based on the ultra-stability of STSe, the STSe-based phase change memory shows 65 000 reversible phase change ability. Moreover, the assembled flexible device can show real-time monitoring and recoverability response in sensing human activities in different parts of the body, which proves its effective reusability and potential as wearable electronics. Most importantly, the STSe device presents remarkable working reliability, reflected by excellent endurance over 100 s and long retention over 100 h. These results paved a novel way to utilize STSe phase change materials for flexible memory and wearable electronics with extreme thermal and mechanical stability and brilliant performance.

Ferroelectric field-effect transistors (FeFETs) with semiconductors as the channel material and ferroelectrics as the gate insulator are attractive and/or promising devices for application in nonvolatile memory. In FeFETs, the conductivity states of the semiconductor are utilized to explore the polarization directions of the ferroelectric material. Herein, we report FeFETs based on a few layers of MoS2on a 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3(PMN–PT) single crystal with switchable multilevel states. It was found that the On–Off ratios can reach as high as 106. We prove that the interaction effect of ferroelectric polarization and interface charge traps has a great influence on the transport behaviors and nonvolatile memory characteristics of MoS2/PMN–PT FeFETs. In order to further study the underlying physical mechanism, we have researched the time-dependent electrical properties in the temperature range from 300 to 500 K. The separation of effects from ferroelectric polarization and interfacial traps on electrical behaviors of FeFETs provides us with an opportunity to better understand the operation mechanism, which suggests a fantastic way for multilevel, low-power consumption, and high-density nonvolatile memory devices.

Lithium–sulfur batteries are promising next-generation energy storage systems with high theoretical specific capacity. Despite extensive research efforts, it is still challenging to rationally design electrocatalysts with fast kinetics and effective adsorption of polysulfides. Herein, Fe-doped ReS2(Fe–ReS2) ultrathin nanosheets are prepared as an electrocatalyst to trap the intermediates and accelerate the sulfur reduction reaction kinetics. Density functional theory calculations combined with activation energies in the multistep sulfur reduction reaction reveal that the Fe–ReS2considerably reduces the activation energy and optimizes the optimum adsorption strength of polysulfides and catalytic activity. The Fe–ReS2/S exhibits a highly reversible discharge capacity of 882.3 mA h g–1at 1 C. For 500 cycles, the capacity fade rate is 0.013% per cycle. Moreover, in situ Raman spectroscopy measurements further confirmed that both sulfur reduction and oxidation processes were significantly enhanced by Fe–ReS2.