Search

A new polymer in polymer structure was constructed, incorporating two distinct polymers: the rigid PVDF–HFP as the porous framework and the flexible PEO, which served both as the filler and the liquid electrolyte absorber. For the first time, the polymeric porous structure was engineered using CDs, which could be recycled through washing and reused in subsequent pore creation processes. The high porosity and robust structure of the PVDF–HFP framework ensured effective deposition of PEO and absorption of the electrolyte. The resulting gel polymer electrolytes (GPEs) exhibited excellent conductivity, a wide electrochemical stability window, and considerable lithium-ion transference numbers at room temperature. These GPEs were employed in lithium metal batteries (LMBs), which exhibited exceptional cycling stability exceeding 3000 h, high rate capability, and a coulombic efficiency of nearly 100%. Both SEM and XPS investigations of lithium anodes dismantled from LMBs after extended cycling revealed the formation of stable solid-electrolyte interphase (SEI) layers on the lithium surface, which effectively hindered dendrite growth and minimized anode corrosion. This research offers a solution for fabricating high-performance GPEs for LMBs with long cycle lifespans while also introducing a new technique for preparing porous polymer materials using CDs. [ABSTRACT FROM AUTHOR]

Customizable porous carbon structures are critical for high‐performance electrode materials, and the modulation of the pore parameters at different levels remains a great challenge. For supercapacitors, the preferred carbon materials should own high specific capacitance, nice rate performance, large density, low self‐discharge, and high mass‐loading, which could be accomplished by sub‐nanometer pores (0.5–1.0 nm). Herein, a new method of using carbon dots (CDs) as self‐templates is reported to produce porous carbon with uniform pore diameters of 0.64–0.80 nm. As a result, the optimal sample with a high packing density (0.81 g cm−3) displays outstanding capacitances (gravimetric 515.5 F g−1, areal 5.16 F cm−2, and volumetric 417.6 F cm−3 respectively at 1 A g−1) at the commercial‐level mass‐loading of 10 mg cm−2. The assembled high‐loading symmetric supercapacitor shows a high energy density of 22.3 Wh kg−1 at 3500 W kg−1, as well as a long cycle stability (99.9% of retention rate after 10 000 cycles at 2 A g−1) in an ultrawide voltage range of 1.4 V with aqueous electrolytes. This work suggests a micropore‐forming strategy for the preferred porous carbon, which can be applied in supercapacitors, batteries, filters, adsorbents, and catalysts. [ABSTRACT FROM AUTHOR]

Mn3O4 is a promising cathode material for aqueous zinc ion batteries (ZIBs) which is a new type of low cost, eco‐friendly, high security energy storage system, while those previously reported electrochemical capacities of Mn3O4 are far from its theoretical value. In this work, Mn3O4 nanoparticles and nitrogen‐doped carbon dots (NCDs) are synthesized together through an in‐situ hydrothermal route, and then calcined to be a nanocomposite in which Mn3O4 nanoparticles are anchored on a nitrogen‐doped carbon skeleton (designated as Mn3O4/NCDs). Although the carbon content is only 3.9 wt.% in the Mn3O4/NCDs, the NCDs‐derived carbon skeleton provides an electrically conductive network and a stable structure. Such a special nanocomposite has a large specific surface area, plenty of active sites, excellent hydrophilicity and good electronic conductivity. Owing to these structural merits, the Mn3O4/NCDs electrode exhibits a preeminent specific capacity of 443.6 mAh g−1 and 123.3 mAh g−1 at current densities of 0.1 and 1.5 A g−1 in ZIBs, respectively, which are far beyond the bare Mn3O4 nanoparticles synthesized under the similar condition. The electrochemical measurement results prove that carbon dots, as a new type of carbon nanomaterials, have strong ability to modify and improve the performance of existing electrode materials, which may push these electrode materials forward to practical applications. [ABSTRACT FROM AUTHOR]