Achieving Electronic Engineering of Vanadium Oxide-Based 3D Lithiophilic Sandwiched-Aerogel Framework for Ultrastable Lithium Metal Batteries.

Lithium (Li) metal is one of the most promising anode materials for the next-generation batteries, which owns superior specific capacity and energy density. Unfortunately, lithium dendrites that is formed during the charging/discharging process tends to induce capacity degradation and thus short lifespan. In this study, the vanadium oxide (V2O5) and nitrogen-doped vanadium oxide (N-V2O3, N-VO0.9)-modified three-dimensional (3D) reduced graphene oxide ((N)-VOx@rGO) with tunable electronic properties are demonstrated to enable the dendrite-free Li deposition. The soft lithiophilic rGO as the scaffold can provide sufficient void space for Li storage. Meanwhile, the rigid (N)-VOx uniformly anchored on rGO can perfectly maintain the 3D structure, which is crucial for Li to enter the inner space of the 3D framework. Consequently, the (N)-VOx@rGO electrodes achieve dendrite-free electrodeposition under the multifarious deposition capacity and current densities. Compared with the bare lithium electrodes, the asymmetrical cells of (N)-VOx@rGO anode can cycle stably up to 400 h at 2 mA cm-2 current density, together with a low nucleation overpotential of ∼20 mV.

Breathable and Wearable Strain Sensors Based on Synergistic Conductive Carbon Nanotubes/Cotton Fabrics for Multi-directional Motion Detection.

Flexible strain-sensitive sensors have been receiving intensive attention in many aspects ranging from human motion capture to health-related signal monitoring. However, the fabric strain sensor with multi-directional sensing capability, besides having a wide strain range and high response sensitivity, is still very challenging and deserves further exploration. Here, we have prepared a wearable cotton fabric strain sensor uniformly decorated with single-walled carbon nanotubes through a facile solution process. The unique hierarchical architecture of the cotton fabric woven from twisted yarns combined with the conductive carbon nanotube network endows the fabric strain sensors with attractive performance, including low detection limit, large workable strain range, fascinating stability and durability, excellent direction-dependent strain response, and good air permeability. The strain sensor without polymer encapsulation can not only monitor subtle and large multi-directional motions but also fit well to the human body with satisfactory comfort, demonstrating its potential application in wearable electronics and intelligent clothing.

Molecular Bridging Enables Isolated Iron Atoms on Stereoassembled Carbon Framework To Boost Oxygen Reduction for Zinc-Air Batteries.

Realizing the synergy between active site regulation and rational structural engineering is essential in the electrocatalysis community but still challenging. Here, a matrix-confined co-pyrolysis strategy based on molecular bridging is demonstrated to realize highly dispersed Fe atoms on stereoassembled carbon framework. Both polyacrylonitrile matrix and organic linker from metal-organic frameworks (MOFs) provide sufficient N-anchoring sites for the generation of Fe-N4 moieties. A high Fe loading of 2.9 wt.% is readily achieved based on the scalable approach without post-treatment. Owing to the presence of highly exposed Fe-N-C sites and well-tuned pore structures, isolated Fe atoms on porous carbon nanofiber framework (Fe-SA/NCF) exhibits decent oxygen reduction activity and stability in alkaline conditions via a near four-electron path, demonstrating superior performance as air cathode for zinc-air batteries (ZABs) to commercial Pt/C catalyst.

Ultrasensitive and Wearable Carbon Hybrid Fiber Devices as Robust Intelligent Sensors.

The growing applications of wearable electronics, electronic textiles, and biomedical devices have sparked explosive demand for high-performance flexible sensors. Herein, we report a facile approach for fabricating a highly sensitive carbon hybrid fiber, which is composed of a graphene fiber skeleton and carbon nanotube (CNT) branches. In this hierarchical fiber, in situ grown CNTs prohibit the stacking of graphene sheets and bridge graphene layers simultaneously, making the hybrid fiber fluffy and conductive. Due to the well-designed architecture, the assembled fiber sensor exhibits satisfactory performance with a high gauge factor (up to 1127), a fast response time (less than 70 ms), and excellent reliability and stability (>2000 cycles). This work provides a feasible and scalable pathway for the fabrication of ultrasensitive fiber-based sensors, achieving the full realization of monitoring human physiological signals and architecting a real-time human-machine controlling system. Moreover, these practical sensors are used to monitor the sitting posture to prevent cervical spondylosis and lumbar disc herniation.

Ultrafast Microwave Polarizing Electrons to Form Vertically Aligned Metal Hybrids as Lithiophilic Buffer for Lithium-Metal Batteries.

Lithium-metal batteries (LMBs) have attracted great attention because of their high theoretical capacity and low electrochemical potential. However, uncontrollable Li dendrite growth and significant volume expansion result in safety issues that largely limit their practical applications. Herein, we explore a microwave-assisted strategy for the rapid synthesis of vertically aligned metal hybrids on Cu foil (VAMH@CF). Such an elaborate architecture of VAMH provides a lithiophilic buffer layer after prelithiation, offering vast nucleation sites/seeds for Li deposition (Li@VAMH@CF) and lower nucleation overpotential. Consequently, Li@VAMH@CF exhibits an outstanding cyclability with a long lifespan (up to 5500 cycles) and a low voltage hysteresis (28 mV) in a symmetrical cell at 3 mA cm-2. LiFePO4||Li@VAMH@CF full cells deliver a reversible capacity of about 140 mAh g-1 for 200 cycles, further demonstrating opportunities of the microwave-involved strategy for optimizing Li-metal anodes.