Ao Xiang,Deyou Shi,Peng Chen,Zhongjun Li,Quan Tu,Dahui Liu,Xiangguang Zhang,Jun Lu,Yan Jiang,Ze Yang,Pei Hu
Developing cost-effective cathode materials is conducive to accelerating the commercialization of sodium-ion batteries. Na4Fe3(PO4)2P2O7(NFPP) has attracted extensive attention owning to its high theoretical capacity, stable structure, and low cost of raw materials. However, its inherent low conductivity hinders its further application. Herein, carbon-coated NFPP nanospheres are anchored to crumpled MXene nanosheets by an electrostatic self-assembly; this cross-linked structure induced by CTAB not only significantly expands the contact area between particles and improves the electronic conductivity, but also effectively reduces the aggregation of NFPP nanoparticles. The as-designed Na4Fe3(PO4)2(P2O7)@C/Ti3C2Tx(NFPP@MX) cathode exhibits a high discharge capacity (106.1 mAh g−1g at 0.2 C), good rate capability (60.4 mAh g−1at 10 C), and a long-life cyclic stability (85.2% capacity retention after 1000 cycles at 1 C). This study provides an effective strategy for the massive production of high-performance NFPP cathodes and broadens the application of MXene in the modification of other cathode materials.
Wen-Tao Wang,Nadia Batool,Tian-Heng Zhang,Jiao Liu,Xiao-Feng Han,Jing-Hua Tian,Ruizhi Yang
The oxygen reduction reaction (ORR) plays a key role in many efficient and clean energy systems, specifically in fuel cells and metal–air batteries. As a widely used commercial ORR catalyst, Pt/C has the limitations of high price and scarce reserves. Metal–nitrogen–carbon (M–N–C) is considered as one of the most promising alternatives to replace noble metal catalysts. However, how to balance the high catalytic activity and stability is still a major challenge. In this study, we report a novel non-noble metal composited catalyst, Fe–N–C@Ti3C2Tx, synthesized by a facile separated pyrolysis strategy. The Fe-doped Zeolitic Imidazolate Framework-8 (ZIF-8) was converted to Fe–N–C by carbonization firstly, which was then mixed with few-layered Ti3C2Tx and pyrolyzed together to obtain Fe–N–C@Ti3C2Tx composites. This separated pyrolysis strategy can not only ensure the high carbonization temperature required by Fe–N–C for high catalytic activity but also avoid the damage of MXene caused by high pyrolysis temperature. Thus, Fe–N–C@Ti3C2Tx exhibited excellent ORR activity and stability in alkaline solution, including a half-wave potential of 0.887 V vs. RHE, limiting diffusion current density of 6.3 mA cm−2, and even no attenuation after 10 000 cycles in 0.1 M KOH. Meanwhile, it also exhibited surprisingly good performance in acidic solution, with a half-wave potential of 0.777 V vs. RHE, limiting diffusion current density of 5.7 mA cm−2, and only 11 mV attenuation after 10 000 cycles in 0.1 M HClO4. The superior ORR performance of the synthesized Fe–N–C@Ti3C2Tx could be attributed to the strong coupling effect between Fe–N–C and MXene, the reduced intrinsic and charge transfer impedance, and the increased electrochemically active surface area. This work here provides a new strategy for the development of M–N–C based non-noble metal-based catalysts with high activity and stability, and a promising future for applications in fuel cells and metal–air batteries.
Homologous interfacial engineering enables atomic anchoring of P-CNPs onto C-Ti 3 C 2 T x via Ti-O-C covalent bonds. • Hierarchical architecture acts as wave confinement walls, inducing Maxwell-Wagner polarization and extended dissipation paths. • EMI SE reaches 75.44 dB at 4 wt% loading with absorption as the dominant shielding mechanism. • Composite achieves 215.4 MPa tensile strength, overcoming conductivity–mechanical integrity trade-off. Achieving a synergistic balance between electromagnetic interference (EMI) shielding and mechanical robustness in carbon fiber-reinforced polymers (CFRPs) remains a fundamental challenge due to the long-standing trade-off between electrical conductivity and mechanical integrity. Here, we report a homologous interfacial reinforcement strategy to engineer a hierarchical architecture via the atomic-scale anchoring of C-Ti 3 C 2 T X and polyimide/polydopamine-derived carbon nanoparticles (P-CNPs). The formation of Ti-O-C covalent bonds yields a continuous hybrid network that effectively suppresses MXene restacking. This hierarchical configuration acts as electromagnetic-wave confinement walls, inducing pronounced Maxwell-Wagner polarization and extending energy-dissipation pathways through multiple internal reflections. The composite achieves a high EMI shielding effectiveness (SE) of 75.44 dB at a low filler loading of 4 wt%, while maintaining an excellent tensile strength of 215.4 MPa. The homologous interfacial engineering strategy presented here offers a transformative route for simultaneously integrating mechanical robustness with absorption-enhanced EMI functionality, providing new design insights for integrated materials in aerospace and microelectronics. Download: Download high-res image (324KB) Download: Download full-size image
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