Self-Assembly 3D Porous Crumpled MXene Spheres as Efficient Gas and Pressure Sensing Material for Transient All-MXene Sensors

Environmentally friendly degradable sensors with both hazardous gases and pressure efficient sensing capabilities are highly desired for various promising applications,including environmental pollution monitoring/prevention,wisdom medical,wearable smart devices,and artificial intelligence.However,the transient gas and pressure sensors based on only identical sensing material that concurrently meets the above detection needs have not been reported.Here,we present transient all-MXene NO_(2) and pressure sensors employing three-dimensional porous crumpled MXene spheres prepared by ultrasonic spray pyrolysis technology as the sensing layer,accompanied with water-soluble polyvinyl alcohol substrates embedded with patterned MXene electrodes.The gas sensor achieves a ppb-level of highly selective NO_(2) sensing,with a response of up to 12.11%at 5 ppm NO_(2) and a detection range of 50 ppb-5 ppm,while the pressure sensor has an extremely wide linear pressure detection range of 0.14-22.22 kPa and fast response time of 34 ms.In parallel,all-MXene NO_(2) and pressure sensors can be rapidly degraded in medical H_(2)O_(2) within 6 h.This work provides a new avenue toward environmental monitoring,human physiological signal monitoring,and recyclable transient electronics.

Interface Reversible Electric Field Regulated by Amphoteric Charged Protein-Based Coating Toward High-Rate and Robust Zn Anode

Metallic interface engineering is a promising strategy to stabilize Zn anode via promoting Zn^(2+) uniform deposition.However,strong interactions between the coating and Zn^(2+) and sluggish transport of Zn^(2+) lead to high anodic polarization.Here,we present a bio-inspired silk fibroin(SF)coating with amphoteric charges to construct an interface reversible electric field,which manipulates the transfer kinetics of Zn^(2+) and reduces anodic polarization.The alternating positively and negatively charged surface as a build-in driving force can expedite and homogenize Zn^(2+) flux via the inter-play between the charged coating and adsorbed ions,endowing the Zn-SF anode with low polarization voltage and stable plating/stripping.Experimental analyses with theo-retical calculations suggest that SF can facilitate the desolvation of[Zn(H_(2)O)_(6)]^(2+) and provide nucleation sites for uniform deposition.Consequently,the Zn-SF anode delivers a high-rate performance with low voltage polarization(83 mV at 20 mA cm^(−2)) and excellent stability(1500 h at 1 mA cm^(−2);500 h at 10 mA cm^(−2)),realizing exceptional cumulative capacity of 2.5 Ah cm^(−2).The full cell coupled with Zn_(x)V_(2)O_(5)·nH_(2)O(ZnVO)cathode achieves specific energy of~270.5/150.6 Wh kg^(−1)(at 0.5/10 A g^(−1))with-99.8% Coulombic efficiency and retains~80.3%(at 5.0 A g^(−1))after 3000 cycles.