Highly active two‐dimensional (2D) nanocomposites, integrating the unique merits of individual components and synergistic effects of composites, are greatly desired for flexible sensing device applications. Although 2D transition metal carbides and nitrides (MXenes) combined with their high metallic conductivity and versatile surface chemistry have shown its huge potential for sensing reactions, it still remains a major challenge to construct functional materials with intriguing sensing performance at room temperature (RT). Herein, we used an integration of density functional theory (DFT) simulations and bulk electrosensitive measurements to show high electrocatalytic sensitivity of polyaniline/MXene (PANI/Ti₃C₂T _x) nanocomposites. Thanks to the synergistic properties of nanocomposites and high catalytic/absorption capacity of Ti₃C₂T _x MXene, PANI nanoparticles are rationally decorated on Ti₃C₂T _x nanosheet surface via in situ polymerization by low temperature approach to induce remarkable detection sensitivity, rapid response/recovery rate, and mechanical stability at RT. This study offers a versatile platform to use MXenes to fabricate 2D nanocomposites materials for high‐performance flexible gas sensors.

Design of cost-effective, highly efficient and stable bifunctional electrocatalysts for overall water splitting is necessary for renewable energy systems. In this study, NiCoP nanowire arrays grown on 3D Ni foam (NiCoP NWAs/NF) were successfully synthesized by a two-step method, which were developed as novel bifunctional electrocatalysts for evaluating in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Their special cone nanostructure and bifunctional crystal structure enable the electrocatalysts to display remarkable electrocatalytic performance and stability for OER and HER (maintained for 28 h in the long-term HER and OER stability test with slight attenuation). The electrodes have very low overpotentials of 197 mV and 370 mV for HER and OER in 1.0 M KOH at a high current density of 100 mA cm⁻², respectively. All the merits can be attributed to several parameters: the inherent nature of transition metal phosphides, the presence of a bimetal synergetic effect, special morphology design, and the formation of “secondary” electrocatalysts on the surface of NiCoP. Meanwhile, the excellent bifunctional electrocatalysts can be developed as both anode and cathode of an alkaline electrolyzer (1.0 M KOH) which needs a cell voltage of 1.64 V to achieve 20 mA cm⁻² current density.

Although Mn²⁺ additives alleviate the dissolution issue of Mn-based cathodes in aqueous zinc–ion batteries (ZIBs), problems including complex side reactions and abnormal capacity fluctuation pose new challenges for their large-scale applications. In virtue of manganese oxide based on preeminent cation-pillar engineering, we elaborate the origin of capacity fluctuation, which is found to be correlated with the unique Mn²⁺ behavior. For the first time, we figure out new metrics such as effective cycling percentage (η) and maximum Mn²⁺ contribution ratio (ε) to reappraise the electrochemical performance of the current Mn-based ZIBs via a new capacity evaluation protocol, i.e., Mn-based competitive capacity evolution (Mn-CCE). The universality of the protocol and its metrics were further verified via quantitative analyses of the reported Mn-based ZIBs. More significantly, the failure of Mn-based electrodes is demonstrated to be rescuable via facile acid treatment, which is expected to quintuple the lifespan of batteries. The findings can provide new insights to understand the electrochemical behaviors, serve as the assessment criteria, and further guide the development of Zn/Mn-related devices for practical applications.