To tackle the issue of the low specific capacity (372 mA h g⁻¹) of graphite as the anode material for lithium-ion batteries (LIBs), an effective and controllable strategy was developed to construct porous bimetallic Co/Zn embedded N-doped carbon (Co–Zn/N–C) polyhedral nanocages via annealing a ZIF-8@ZIF-67 precursor at 800 °C under Ar atmosphere. The results clearly displayed that metallic Co and Zn particles are uniformly dispersed in the carbon matrix. Porous Co–Zn/N–C polyhedral nanocages have a large specific surface area of 349.12 m² g⁻¹ and contain plenty of micropores and mesopores, which benefit from the carbonization of organic ligands and the catalytic effect of cobalt in the calcination process. As anodes for LIBs, the porous Co–Zn/N–C polyhedral nanocages showed an initial discharge capacity of 809 mA h g⁻¹ and a capacity retention of 702 mA h g⁻¹ after 400 cycles at a current density of 0.2 A g⁻¹. Furthermore, a reversible capacity of 444 mA h g⁻¹ was obtained at a much higher current density of 2 A g⁻¹. The improved electrochemical performance was attributed to the synergistic effect of Zn and Co, the unique porous hollow structure as well as N doping, which relieved the impact of volume changes, maintained perfect electrical conductivity throughout the electrode and enhanced the electrochemical activities of lithium storage.

To further improve the catalytic carbonization efficiency of polymer composites for the formation of compact protective layers in the combustion process, a novel type of Fe-CNTs was prepared in large scale. The Fe-CNTs were used as nanofillers to efficiently improve catalytic carbonization, flame retardancy, and mechanical performances of epoxy resin (EP). With the incorporation of 6 wt% Fe-CNTs, the LOI value of the EP/Fe-CNTs nanocomposites was improved to 35.0 and the UL-94 V-1 rating was passed with an average (t₁ + t₂) value of 13.3. As compared to pure EP, the PHRR, THR, and TSP of EP/6 wt% Fe-CNTs nanocomposites decreased by 30.7%, 39.1%, and 48.6%, respectively. The significantly improved flame retardancy could be attributed to the compact carbonaceous ceramic layers, which significantly retarded the transfer of heat and combustible gas between the EP nanocomposites and the flame zone. Moreover, the EP/Fe-CNTs nanocomposites exhibited excellent impact and tensile strength performances due to the formation of a strong three-dimensional network structure in the EP matrix.

Sodium-ion batteries (SIBs) have been attracting considerable attention as a promising candidate for large-scale energy storage because of the abundance and low-cost of sodium resources. However, lack of appropriate anode materials impedes further applications. Herein, a novel self-template strategy is designed to synthesize uniform flowerlike N-doped hierarchical porous carbon networks (NHPCN) with high content of N (15.31 at.%) assembled by ultrathin nanosheets via a self-synthesized single precursor and subsequent thermal annealing. Relying on the synergetic coordination of benzimidazole and 2-methylimidazole with metal ions to produce a flowerlike network, a self-formed single precursor can be harvested. Due to the structural and compositional advantages, including the high N doping, the expanded interlayer spacing, the ultrathin two-dimensional nano-sized subunits, and the three-dimensional porous network structure, these unique NHPCN flowers deliver ultrahigh reversible capacities of 453.7 mAh·g⁻¹ at 0.1 A·g⁻¹ and 242.5 mAh·g⁻¹ at 1 A·g⁻¹ for 2,500 cycles with exceptional rate capability of 5 A·g⁻¹ with reversible capacities of 201.2 mAh·g⁻¹. The greatly improved sodium storage performance of NHPCN confirms the importance of reasonable engineering and synthesis of hierarchical carbon with unique structures.

Developing suitable electrode materials for electrochemical energy storage devices by biomorph assisted design has become a fascinating topic due to the fantastic properties derived from bio-architectures. Herein, zephyranthes-like Co₂NiSe₄ arrays grown on butterfly wings derived three-dimensional (3D) carbon framework (Z-Co₂NiSe₄/BWC) is fabricated via hydrothermal assembly and further conversion method. Benefiting from its unique structure and multi-components, the obtained Z-Co₂NiSe₄/BWC electrode for supercapacitor delivers an excellent specific capacitance of 2,280 F·g⁻¹ at 1 A·g⁻¹. Impressively, the constructed asymmetric supercapacitor using Co₂NiSe₄/BWC as positive electrode and activated butterfly wings carbon as negative electrode acquires a high energy density of 42.9 Wh·kg⁻¹ at a power density of 800 W·kg⁻¹ with robust stability of 94.6% capacitance retention at 10 A·g⁻¹ after 5,000 cycles. Moreover, the Z-Co₂NiSe₄/BWC as anode for sodium-ion batteries exhibits a high specific capacity of 568 mAh·g⁻¹ at 0.1 A·g⁻¹ and high cycling stability (maintaining 80.1% of the second cycle after 100 cycles). The outstanding electrochemical performances are ascribed to that the synergistic effect of bimetallic selenides and N-doped carbon improves electrochemical activities and conductivity. One-dimensional (1D) nanoneedles grown on 3D porous framework increase the exposure of redox-active sites, endow adequate transmission channels of electrons/ions, and guarantee stability of the electrode during charge/discharge processes. This study will shed light on the avenue towards extending such nanohybrids to excellent energy storage applications.