High-Performance Biomass-Based Flexible Solid-State Supercapacitor Constructed of Pressure-Sensitive Lignin-Based and Cellulose Hydrogels

Employing renewable, earth-abundant, environmentally friendly, low-cost natural materials to design flexible supercapacitors (FSCs) as energy storage devices in wearable/portable electronics represents the global perspective to build sustainable and green society. Chemically stable and flexible cellulose and electroactive lignin have been employed to construct a biomass-based FSC for the first time. The FSC was assembled using lignosulfonate/single-walled carbon nanotube_HNO₃ (Lig/SWCNT_HNO₃) pressure-sensitive hydrogels as electrodes and cellulose hydrogels as an electrolyte separator. The assembled biomass-based FSC shows high specific capacitance (292 F g^–1 at a current density of 0.5 A g^–1), excellent rate capability, and an outstanding energy density of 17.1 W h kg^–1 at a power density of 324 W kg^–1. Remarkably, the FSC presents outstanding electrochemical stability even suffering 1000 bending cycles. Such excellent flexibility, stability, and electrochemical performance enable the designed biomass-based FSCs as prominent candidates in applications of wearable electronic devices

Ultrasensitive Mg²⁺-Modulated Carbon Nanotube/Tannic Acid Aerogels for High-Performance Wearable Pressure Sensors

Three-dimensional (3D) carbon nanotube-based porous networks have received considerable attention as active nanomaterials for flexible/wearable sensor applications due to their excellent conductivity and mechanical flexibility. Herein, ultralight, biocompatible, and conductive SWCNT/tannic acid (TA) and Mg2+/SWCNT/TA aerogels have been facilely fabricated using TA as a dispersion reagent and crosslinker and Mg2+ to introduce a metal–phenolic network. The construction of a SWCNT@TA core–shell structure and the low CNT concentration of SWCNT/TA3:3 contribute to a high linear sensitivity of 432 kPa–1 in a wide pressure range (0.014–28 kPa), while Mg2+ modulation endows Mg2+/SWCNT/TA1:1 with an ultrahigh linear sensitivity of 13662 kPa–1 in a pressure range of 0.014–1.05 kPa. The superior sensing performance of as-prepared aerogels, including high sensitivity, wide working range, low detection limit (14 Pa), and fast stimuli-response (200–300 ms), enables them to detect tiny changes in human biosignals and imperceptible vibration, which show great potential in applications of health monitoring, human–machine interfaces, and various flexible electronics

Ultrasensitive Mg²⁺-Modulated Carbon Nanotube/Tannic Acid Aerogels for High-Performance Wearable Pressure Sensors

Three-dimensional (3D) carbon nanotube-based porous networks have received considerable attention as active nanomaterials for flexible/wearable sensor applications due to their excellent conductivity and mechanical flexibility. Herein, ultralight, biocompatible, and conductive SWCNT/tannic acid (TA) and Mg2+/SWCNT/TA aerogels have been facilely fabricated using TA as a dispersion reagent and crosslinker and Mg2+ to introduce a metal–phenolic network. The construction of a SWCNT@TA core–shell structure and the low CNT concentration of SWCNT/TA3:3 contribute to a high linear sensitivity of 432 kPa–1 in a wide pressure range (0.014–28 kPa), while Mg2+ modulation endows Mg2+/SWCNT/TA1:1 with an ultrahigh linear sensitivity of 13662 kPa–1 in a pressure range of 0.014–1.05 kPa. The superior sensing performance of as-prepared aerogels, including high sensitivity, wide working range, low detection limit (14 Pa), and fast stimuli-response (200–300 ms), enables them to detect tiny changes in human biosignals and imperceptible vibration, which show great potential in applications of health monitoring, human–machine interfaces, and various flexible electronics

Optimization of Flexible Nacre-Like Cellulose Nanofiber Films by a Covalent Overlapping Method: Excellent Thermal Conductivity and Superior Flame Resistance

Facing the explosive growth of heat flux in microelectronic equipment, advanced thermal management materials should not only ensure the safe and stable operation of equipment, but also have the ability to withstand fire risks. Carbon materials such as graphene are subject to many restrictions in use due to their inherent high conductivity. Hexagonal boron nitride (h-BN) is often used to blend with polymers to prepare flexible thermal management materials due to its excellent electrical insulation and thermal conductivity. However, its further application is limited by its insufficient flame resistance and limited improvement of thermal conductivity at low filling levels. In this paper, urea-assisted ball milling is used to achieve the amination of boron nitride nanosheets (BNNS) and black phosphorus (BP), which creates the covalent bond between the filler and the cellulose. With the overlapping between small-size BP and large-size BNNS, the thermal conductivity, flame resistance, and mechanical properties of the film are significantly enhanced. Accordingly, the cellulose nanofiber (CNF)-based film has a high thermal conductivity of 42.29 W m–1 K–1 at 50 wt % loading (40 wt % BNNS-NH2 and 10 wt % BP-NH2), which is 777% higher than that of pure CNF. In addition, the peak heat release rate and total heat release of CBP10 decrease by 80.3 and 64.7%, respectively, compared with pure CNF, and the residue is more complete and denser, indicating that the film can effectively reduce and delay the fire hazard

Ultrasensitive Mg²⁺-Modulated Carbon Nanotube/Tannic Acid Aerogels for High-Performance Wearable Pressure Sensors

Three-dimensional (3D) carbon nanotube-based porous networks have received considerable attention as active nanomaterials for flexible/wearable sensor applications due to their excellent conductivity and mechanical flexibility. Herein, ultralight, biocompatible, and conductive SWCNT/tannic acid (TA) and Mg2+/SWCNT/TA aerogels have been facilely fabricated using TA as a dispersion reagent and crosslinker and Mg2+ to introduce a metal–phenolic network. The construction of a SWCNT@TA core–shell structure and the low CNT concentration of SWCNT/TA3:3 contribute to a high linear sensitivity of 432 kPa–1 in a wide pressure range (0.014–28 kPa), while Mg2+ modulation endows Mg2+/SWCNT/TA1:1 with an ultrahigh linear sensitivity of 13662 kPa–1 in a pressure range of 0.014–1.05 kPa. The superior sensing performance of as-prepared aerogels, including high sensitivity, wide working range, low detection limit (14 Pa), and fast stimuli-response (200–300 ms), enables them to detect tiny changes in human biosignals and imperceptible vibration, which show great potential in applications of health monitoring, human–machine interfaces, and various flexible electronics

Ultrasensitive Mg²⁺-Modulated Carbon Nanotube/Tannic Acid Aerogels for High-Performance Wearable Pressure Sensors

Three-dimensional (3D) carbon nanotube-based porous networks have received considerable attention as active nanomaterials for flexible/wearable sensor applications due to their excellent conductivity and mechanical flexibility. Herein, ultralight, biocompatible, and conductive SWCNT/tannic acid (TA) and Mg2+/SWCNT/TA aerogels have been facilely fabricated using TA as a dispersion reagent and crosslinker and Mg2+ to introduce a metal–phenolic network. The construction of a SWCNT@TA core–shell structure and the low CNT concentration of SWCNT/TA3:3 contribute to a high linear sensitivity of 432 kPa–1 in a wide pressure range (0.014–28 kPa), while Mg2+ modulation endows Mg2+/SWCNT/TA1:1 with an ultrahigh linear sensitivity of 13662 kPa–1 in a pressure range of 0.014–1.05 kPa. The superior sensing performance of as-prepared aerogels, including high sensitivity, wide working range, low detection limit (14 Pa), and fast stimuli-response (200–300 ms), enables them to detect tiny changes in human biosignals and imperceptible vibration, which show great potential in applications of health monitoring, human–machine interfaces, and various flexible electronics

Hypervalent Iodine-Mediated Oxidative Rearrangement of N–H Ketimines: An Umpolung Approach to Amides

An umpolung approach to amides via hypervalent iodine-mediated oxidative rearrangement of N–H ketimines under mild reaction conditions is described. This strategy provides target amides with excellent selectivity in good yields. In addition, preliminary mechanistic studies demonstrated that the migration preference depends on both steric and electronic effects of the migrating groups

Ynamides as Racemization-Free Coupling Reagents for Amide and Peptide Synthesis

A highly efficient, two-step, one-pot synthetic strategy for amides and peptides was developed by employing ynamides as novel coupling reagents under extremely mild reaction conditions. The ynamides not only are effective for simple amide and dipeptide synthesis but can also be used for peptide segment condensation. Importantly, no racemization was detected during the activation of chiral carboxylic acids. Excellent amidation selectivity toward amino groups in the presence of −OH, −SH, −CONH₂, ArNH₂, and the NH of indole was observed, making the protection of these functional groups unnecessary in amide and peptide synthesis

Stable Interstrand Cross-Links Generated from the Repair of 1,<i>N</i>⁶‑Ethenoadenine in DNA by α‑Ketoglutarate/Fe(II)-Dependent Dioxygenase ALKBH2

DNA cross-links severely challenge replication and transcription in cells, promoting senescence and cell death. In this paper, we report a novel type of DNA interstrand cross-link (ICL) produced as a side product during the attempted repair of 1,N6-ethenoadenine (εA) by human α-ketoglutarate/Fe(II)-dependent enzyme ALKBH2. This stable/nonreversible ICL was characterized by denaturing polyacrylamide gel electrophoresis analysis and quantified by high-resolution LC–MS in well-matched and mismatched DNA duplexes, yielding 5.7% as the highest level for cross-link formation. The binary lesion is proposed to be generated through covalent bond formation between the epoxide intermediate of εA repair and the exocyclic N6-amino group of adenine or the N4-amino group of cytosine residues in the complementary strand under physiological conditions. The cross-links occur in diverse sequence contexts, and molecular dynamics simulations rationalize the context specificity of cross-link formation. In addition, the cross-link generated from attempted εA repair was detected in cells by highly sensitive LC–MS techniques, giving biological relevance to the cross-link adducts. Overall, a combination of biochemical, computational, and mass spectrometric methods was used to discover and characterize this new type of stable cross-link both in vitro and in human cells, thereby uniquely demonstrating the existence of a potentially harmful ICL during DNA repair by human ALKBH2