Highly active electrocatalysts of iron phthalocyanine by MOFs for oxygen reduction reaction under alkaline solution

Precise construction of lithiophilic sites by diyne-linked phthalocyanine polymer for suppressing metallic lithium dendrite

Uncontrolled growth of lithium dendrite is the key challenge that impedes the practical application of Li anodes in high-energy-density Li-metal batteries. Precisely constructing lithiophilic active sites on the anode surface is expected to be an effective strategy for promoting the anode interfacial properties and alleviating the dendrite growth of lithium. Herein, a diyne-linked phthalocyanine polymer (PcEP) with precise lithiophilic active sites is designed and constructed in a bottom-up manner in situ on the surface of the copper foil via the coupling reaction of tetraethynylphthalocyanine. The lithiophilic electron-rich pyrrolic nitrogen and aza nitrogen in the Pc structure, and the sp-hybridized carbon in the diyne linkage (-CC-CC-) in PcEP can conduct the homogeneous nucleation and deposition processes of lithium, and thus suppress the dendrite growth. This dendrite-free metallic lithium anode exhibits reduced overpotential, high coulombic efficiency (98.6%), and prolonged lifespan (200% longer than that of a Cu anode). These impressive achievements demonstrate that the advanced phthalocyanine polymer might be a promising material for addressing the critical interfacial issues related to the next-generation high-energy-density Li-metal-based storage devices.

Nanostructured transition-metal phthalocyanine complexes for catalytic oxygen reduction reaction

Oxygen reduction reaction (ORR) plays a key role in the field of fuel cells. Efficient electrocatalysts for the ORR are important for fuel cells commercialization. Pt and its alloys are main active materials for ORR. However, their high cost and susceptibility to time-dependent drift hinders their applicability. Satisfactory catalytic activity of nanostructured transition metal phthalocyanine complexes (MPc) in ORR through the occurrence of molecular catalysis on the surface of MPc indicates their potential as a replacement material for precious-metal catalysts. Problems of MPc are analyzed on the basis of chemical structure and microstructure characteristics used in oxygen reduction catalysis, and the strategy for controlling the structure of MPc is proposed to improve the catalytic performance of ORR in this review.

A two-dimensional porous conjugated porphyrin polymer for uniform lithium deposition

Uniform lithium deposition is a benefit to achieving high-energy-density lithium metal batteries. There are many effective methods to suppress the dendritic growth of metallic lithium and promote the application of the lithium anode. However, the designation of lithiophilic sites at the atomic level remains a huge challenge. Herein, a two-dimensional porous conjugated porphyrin polymer linked by two acetylenic linkages from an in situ coupling reaction has been prepared on copper foil and employed as the lithiophilic host. The four electron-rich pyrrolic nitrogen atoms in the porphyrin building block and the linkage electron-rich sp-hybridized carbon atoms were regarded as precise lithiophilic sites, resulting in a decreased nucleation overpotential and dendrite free morphology. With uniform lithium deposition, the electrochemical performance of the electrode was significantly improved in regard to the overpotential, coulombic efficiency and lifespan. This work expands the precise construction of lithiophilic sites at the atomic level and benefits to further development of high-energy density lithium metal batteries.