燃料电池复合石墨双极板基材的研究进展:材料、结构与性能

双极板是燃料电池的重要组成部件,需要满足导电、抗弯强度、耐腐蚀等方面性能的要求。复合石墨双极板具有成本低、耐腐蚀性好、易成型等优势,是双极板的一个重要研究方向。复合石墨双极板的导电功能是由以石墨为代表的导电填料相互连接形成传导网络实现的,抗弯强度及气密等性能则主要依靠树脂固化形成的基体。因此,复合石墨双极板性能不仅受到导电填料以及树脂性能的影响,同时导电填料、树脂固化形成的结构对于极板性能也有着不可忽视的影响。本文总结了导电填料及树脂的性质、改性方法等对于复合石墨极板性能的影响,并分析了分子结构以及制备工艺对于极板结构以及实用性能的影响规律。导电填料与树脂的相容性受到原料表面官能团的影响,并直接影响了导电填料的离散均匀度以及导电填料/树脂的界面性能。通过填料诱导工艺优化导电网络,能够有效提升极板的导电性能。基于对研究现状的总结,本文对复合石墨极板开发的未来发展方向进行了展望。

Study on carbon matrix composite bipolar plates with balance of conductivity and flexural strength

In order to balance the conductivity and flexural strength of graphite composite bipolar plates,the influence of conductive filler on the properties of graphite composite bipolar plate was comprehensively studied by using phenolic resin as binder,natural flake graphite as conductive substrate and functional carbon materials with different structures as auxiliary filler.The results show that the particle size of conductive substrate has an important influence on the conductivity enhancement of auxiliary filler.The influence of conductive particle size on auxiliary filler electrical conductivity improvement was first investigated in this research.The effects of various auxiliary filler concentrations on improving electrical conductivity and flexural strength were then examined.This research has substantial implications for the balance of electrical conductivity and flexural strength of graphite composite bipolar plates.

Pt‑Based Intermetallic Compound Catalysts for the Oxygen Reduction Reaction:Structural Control at the Atomic Scale to Achieve a Win–Win Situation Between Catalytic Activity and Stability

The development of ordered Pt-based intermetallic compounds is an effective way to optimize the electronic characteristics of Pt and its disordered alloys,inhibit the loss of transition metal elements,and prepare fuel cell catalysts with high activity and long-term durability for the oxygen reduction reaction(ORR).This paper reviews the structure–activity characteristics,research advances,problems,and improvements in Pt-based intermetallic compound fuel cell catalysts for the ORR.First,the structural characteristics and performance advantages of Pt-based intermetallic compounds are analyzed and explained.Second,starting with 3d transition metals such as Fe,Co,and Ni,whose research achievements are common,the preparation process and properties of Pt-based intermetallic compound catalysts for the ORR are introduced in detail according to element types.Third,in view of preparation problems,improvements in the preparation processes of Pt-based intermetallic compounds are also summarized in regard to four aspects:coating to control the crystal size,doping to promote ordering transformation,constructing a“Pt skin”to improve performance,and anchoring and confinement to enhance the interaction between the crystal and support.Finally,by analyzing the research status of Pt-based intermetallic compound catalysts for the ORR,prospective research directions are suggested.

The Controllable Design of Catalyst Inks to Enhance PEMFC Performance:A Review

Typical catalyst inks in proton exchange membrane fuel cells(PEMFCs)are composed of a catalyst,its support,an ionomer and a solvent and are used with solution processing approaches to manufacture conventional catalyst layers(CLs).Because of this,catalyst ink formulation and deposition processes are closely related to CL structure and performance.However,catalyst inks with ideal rheology and optimized electrochemical performances remain lacking in the large-scale application of PEMFCs.To address this,this review will summarize current progress in the formulation,characterization,modeling and deposition of catalyst inks.In addition,this review will highlight recent advancements in catalyst ink materials and discuss corresponding complex interactions.This review will also present various catalyst ink dispersion methods with insights into their stability and introduce the application of small-angle scattering and cryogenic transmission electron microscopy(cryo-TEM)technologies in the characterization of catalyst ink microstructures.Finally,recent studies in the kinetic modeling and deposition of catalyst inks will be analyzed.

Modifying Carbon Supports of Catalyst for the Oxygen Reduction Reaction in Vehicle PEMFCs

For current carbon-supported Pt catalysts in vehicle proton exchange membrane fuel cells(PEMFCs),the insufficient stability and durability of carbon supports are severe limitations under operating conditions.This paper adopts the accelerated stress test(AST)method to study the carbon corrosion of catalysts,which is significant to efficiently select the catalysts supports in fuel cells.Graphitized carbon blacks with various surface properties are heated under different conditions,followed by evaluation of their antioxidation capacity with the AST.It is shown that optimally graphitized carbon blacks demonstrate superior stability,retaining a constant quinone/hydroquinone(QH)transition peak potential for over 70,000 AST cycles.A Pt catalyst supported on the selected graphitized carbon exhibits excellent durability at both the rotating disk electrode(RDE)and membrane electrode assembly(MEA)levels.The final specific mass activity(MA)of the optimum catalyst is 47.87 mA/mgPt,which is 2.06 times that of commercial Pt/C(23.31 mA/mgPt)in the RDE tests.The final maximum power density of the optimum catalyst is 525.68 mW/cm^(2),which is 305.52 mW/cm^(2)higher than that of commercial Pt/C after undergoing the AST during the MEA measurements.These results prove that the rational surface features of carbon supports play a vital role in improving the overall fuel cell performance by realizing uniform dispersion of Pt nanoparticles,resisting corrosion,and reinforcing metal-support interactions.