Preparation And Electrochemical Properties Of Biomass-Derived 3D Carbon Matrix Composites

In recent decades,abundant biomass as carbon-rich,sustainable and renewable precursors had provided us with a large number of advanced materials for energy conversion and storage.Especially in recent years,as the most abundant natural biomass in the earth,the3D wood-based carbon composite electrode derived from wood was considered as a 3D current collector with potential application due to its unique self-supporting structure,sustainable source and excellent electrochemical performance.In this paper,carbonization of natural pine wood and functional modification o f the carbon skeleton were used to prepare wood-derived porous carbon-based materials(Carbonnized wood,CW).As a novel carbon support material with three-dimensional vertical pores,it was applied to the diffusion layer of the air self-breathing Proton exchange membrane fuel cell(ASB-PEMFC)and the substrate layer of the electrolytic water hydrogen evolution reactions(HER).The specific research contents and results are as follows:(1)Preparation of CW-based gas diffusion layer and its application in ASB-PEMFC.Using carbonization-impregnation-sintering process,w-GDL is prepared by rational carbonization and hydrophobic treatment of natural pine wood,which can replace commercial carbon paper as the high-efficiency cathode gas diffusion layer(GDL)ele ctrode of ASB-PEMFC.The maximum current density(0.318 A/cm²)and maximum power density(0.102 W/cm²)of the single cell assembled with w-GDL are better than that of the cathode GDL with commercial carbon paper.In addition,after 50 hours,the current density at 0.6 V only fell by 2.5%.The GDL prepared by this method has the advantages of low cost,orderly structure and low mass transfer resistance,which provides a new direction for the design and improvement of ASB-PEMFC cathode GDL.(2)Preparation of Mo₂C/N-C/CW composite self-supporting electrode and HER performance.Using in situ growth method,Mo₂C was grown on wood derived porous carbon scaffold by introducing MOFs as sacrificial template to prepare binderless self-supporting electrode.The results show that the prepared Mo₂C/N-C/CW can achieve the current density of 10m A/cm² with the low overpotential of 106.5 m V(1.0 M KOH)and 130.9 m V(0.5 M H₂SO₄)at the low Tafel slope of 47.8 m V dec^-1(1.0 M KOH)and 75.9 m V dec^-1(0.5 M H₂SO₄),and can maintain the performance stability for at least 60 h.This study provides a new way to explore the design of self-supporting 3D electrodes made of CW@MOFs composite materials,and provides a broad prospect for the potential application of the technical equipment.