Preparation and properties of carbon nanotube/polypropylene nanocomposite bipolar plates for polymer electrolyte membrane fuel cells

This study aims at the fabrication of lightweight and high performance nanocomposite bipolar plates for the application in polymer electrode membrane fuel cells (PEMFCs). The thin nanocomposite bipolar plates (the thickness <1.2 mm) consisting of multiwalled carbon nanotubes (MWCNTs), graphite powder and PP were fabricated by means of compression molding. Three types of polypropylene (PP) with different crystallinities including high crystallinity PP (HC-PP), medium crystallinity PP (MC-PP), low crystallinity PP (LC-PP) were prepared to investigate the influence of crystallinity on the dispersion of MWCNTs in PP matrix. The optimum composition of original composite bipolar plates was determined at 80 wt.% graphite content and 20 wt.% PP content based on the measurements of electrical and mechanical properties with various graphite contents. Results also indicate that MWCNTs was dispersed better in LC-PP than other PP owing to enough dispersed regions in nanocomposite bipolar plates. This good MWCNT dispersion of LC-PP would cause better bulk electrical conductivity, mechanical properties and thermal stability of MWCNTs/PP nanocomposite bipolar plates. In the MWCNTs/LC-PP system, the bulk electrical conductivities with various MWCNT contents all exceed 100 S cm⁻¹. The flexural strength of the MWCNTs/LC-PP nanocomposite bipolar plate with 8 phr of MWCNTs was approximately 37% higher than that of the original nanocomposite bipolar plate and the unnotched Izod impact strength of MWCNTs/LC-PP nanocomposite bipolar plates was also increased from 68.32 J m⁻¹ (0 phr) to 81.40 J m⁻¹ (8 phr), increasing 19%. In addition, the coefficient of thermal expansion of MWCNTs/LC-PP nanocomposite bipolar plate was decreased from 32.91 μm m⁻¹ °C⁻¹ (0 phr) to 25.79 μm m⁻¹ °C⁻¹ (8 phr) with the increasing of MWCNT content. The polarization curve of MWCNTs/LC-PP nanocomposite bipolar plate compared with graphite bipolar plate was also evaluated. These results confirm that the addition of MWCNTs in LC-PP leads to a significant improvement on the cell performance of the nanocomposite bipolar plate.     

Preparation and properties of carbon nanotube-reinforced vinyl ester/nanocomposite bipolar plates for polymer electrolyte membrane fuel cells

Novel multiwalled carbon nanotubes (MWNTs) were prepared using poly(oxypropylene)-backboned diamines of molecular weights M_w 400 and 2000 to disperse acid-treated MWNTs, improving the performance of composite bipolar plates in polymer electrolyte membrane fuel cells. A lightweight polymer composite bipolar plate that contained vinyl ester resin, graphite powder and MWNTs was fabricated using a bulk molding compound (BMC) process. Results demonstrate that the qualitative dispersion of MWNTs crucially determined the resultant bulk electrical conductivity, the mechanical properties and the physical properties of bipolar plates. The flexural strength of the composite bipolar plate with 1 phr of MWNTs was approximately 48% higher than that of the original composite bipolar plate. The coefficient of thermal expansion of the composite bipolar plate was reduced from 37.00 to 20.40 μm m⁻¹ °C⁻¹ by adding 1 phr of MWNTs, suggesting that the composite bipolar plate has excellent thermal stability. The porosity of the composite bipolar plate was also evaluated. Additionally, the bulk electrical conductivity of the composite bipolar plate with different MWNTs types and contents exceeds 100 S cm⁻¹. The results of the polarization curves confirm that the addition of MWNTs leads to a significant improvement on the single cell performance.     

Study on the mesocarbon microbeads/polyphenylene sulfide composite bipolar plates applied for proton exchange membrane fuel cells

Thermoplastic/graphite composite bipolar plates based on polyphenylene sulfide (PPS) and mesocarbon microbeads (MCMB) were prepared by compression molding at a pressure of 40 MPa and 400 °C. Electrical conductivity, bulk density, flexural strength, water and ethanol absorption were determined as function of PPS content. The influences of molding time, actived carbon and carbon fiber on the properties of the composite bipolar plates were investigated, the cross section of the composite plates were analyzed by scanning electron microscope (SEM). We found that the optimized PPS content is 20 wt% and the required molding time is 30 min. In particular, the composite plates containing 20 wt% PPS demonstrated in-plane conductivity as high as 133.7 S cm⁻¹, through-plane conductivity 21.37 S cm⁻¹, in addition to showing the value of density, flexural strength, water and ethanol absorption as 1.98 g cm⁻³, 38.82 MPa, 0.0409 and 0.352 g cm⁻³. The addition of actived carbon degraded all the performance of the bipolar plate, while addition of carbon fiber improved almost all the performance of bipolar plate except bulk density and through-plane conductivity. The performances of fuel cell with this composite bipolar plate were tested, no distinct variation occurred after the composite plates operating in fuel cell. These data indicates the chemical and mechanical stability of the composite plates and their potential application in fuel cell.     

Ex situ evaluation of nanometer range gold coating on stainless steel substrate for automotive polymer electrolyte membrane fuel cell bipolar plate

The bipolar plate in polymer electrolyte membrane (PEM) fuel cell helps to feed reactant gases to the membrane electrode assembly (MEA) and collect current from the MEA. To facilitate these functions, the bipolar plate material should exhibit excellent electrical conductivity and corrosion resistance under fuel cell operating conditions, and simultaneously be of low-cost to meet commercialization enabling targets for automotive fuel cells. In the present work, we focus on the benchmarking of 10 nm gold coated SS316L (a.k.a. Au Nanoclad^®) bipolar plate material through ex situ tests, which is provided by Daido Steel (Japan). The use of nanometer range Au coatings help to retain the noble properties of gold while significantly reducing the cost of the bipolar plate. The area specific resistance of the flat sample is 0.9 mΩ cm² while that for the formed bipolar plate is 6.3 mΩ cm² at compaction force of 60 N cm⁻². The corrosion current density was less than 1 μA cm⁻² at 0.8 V/NHE with air sparge simulating cathodic conditions. Additionally, gold coated SS316L showed anodic passivation of SS316L, thereby exhibiting robustness towards coating defects including surface scratches that may originate during the manufacturing of the bipolar plate. These series of ex situ tests indicate that 10 nm gold coated SS316L has good potential to be considered for commercial bipolar plates in automotive fuel cell stack.     

Electrical and thermal conductivities of novel metal mesh hybrid polymer composite bipolar plates for proton exchange membrane fuel cells

This study prepares novel metal mesh hybrid polymer composite bipolar plates for proton exchange membrane fuel cells (PEMFCs) via inserting a copper or aluminum mesh in polymer composites. The composition of polymer composites consists of 70 wt% graphite powder and 0-2 wt% modified multi-walled carbon nanotubes (m-MWCNTs). Results indicate that the in-plane electrical conductivity of m-MWCNTs/polymer composite bipolar plates increased from 156 S cm⁻¹ (0 wt% MWCNT) to 643 S cm⁻¹ (with 1 wt% MWCNT) (D.O.E. target >100 S cm⁻¹). The bulk thermal conductivities of the copper and aluminum mesh hybrid polymer composite bipolar plates (abbreviated to Cu-HPBP and Al-HPBP) increase from 27.2 W m⁻¹ K⁻¹ to 30.0 W m⁻¹ K⁻¹ and 30.4 W m⁻¹ K⁻¹, respectively. The through-plane conductivities decrease from 37.8 S cm⁻¹ to 36.7 S cm⁻¹ for Cu-HPBP and 22.9 S cm⁻¹ for Al-HPBP. Furthermore, the current and power densities of a single fuel cell using copper or aluminum mesh hybrid polymer composite bipolar plates are more stable than that of using neat polymer composite bipolar plates, especially in the ohmic overpotential region of the polarization curves of single fuel cell tests. The overall performance confirms that the metal mesh hybrid polymer composite bipolar plates prepared in this study are promising for PEMFC application.     

Expanded graphite-based electrically conductive composites as bipolar plate for PEM fuel cell

In this study, expanded graphite-based composite bipolar plates are developed from expanded graphite (EG), which is synthesized by chemical intercalation of natural graphite and rapid expansion at high temperature. The expanded graphite synthesized in this study has an expansion ratio between 75–100 cc/gm. The composite bipolar plate with varying weight percentage of EG gives different bulk density, electrical conductivity, mechanical properties and air tightness. The critical weight percentage of filler content is 50 to achieve the desired electrical conductivity and mechanical properties of bipolar plate as per U.S. DOE targets. The composite bipolar plate with 50 wt% of EG gives bulk density of 1.50 g/cm³, electrical conductivity >120 S/cm, bending strength 54 MPa, modulus 6 GPa and shore hardness 50. I–V characteristic of a cell assembly with EG-based composite plates are similar with the performance of a cell with commercial composite plates. These lightweight bipolar plates reduced the volume and weight of ultimate fuel cell stack and helped in improving the fuel cell performance.     

Fabrication and characterization of micro PEM fuel cells using pyrolyzed carbon current collector plates

A novel fabrication technique for micro proton exchange membrane fuel cells (μPEMFCs) based on carbon-MEMS (C-MEMS) was optimized to yield higher performance cells. Polymer manufacturing is relatively easy compared to directly patterning graphite as is typically done to make fuel cell bipolar plates. In a C-MEMS approach, fuel cell bipolar plates are fabricated by first patterning polymer Cirlex^® sheets. By subsequently pyrolyzing the machined polymer sheets at high temperature in an inert atmosphere, carbon bipolar plates with intricate groove structures to distribute the reactants are obtained. Using an improved assembly technique such as polishing the carbonized plates to minimize the contact resistance between gas diffusion layers (GDL) and bipolar plates, better pyrolysis temperature control and a better end plate design, a μPEMFC with a 0.64 cm² active surface was fabricated using the newly developed bipolar plates. At 1 atm and 25 °C a maximum power density of ∼76 mW cm⁻² was obtained, and at 2 atm and 25 °C ∼85 mW cm⁻² was achieved. These data are comparable with data reported in the literature for μPEMFCs and are a dramatic improvement over earlier results reported for the same C-MEMS based fuel cell. Electrochemical Impedance Spectroscopy (EIS) and cyclic voltammetry were carried out to characterize steady-state and transient characteristics of the novel C-MEMS fuel cell.     

Preparation and properties of functionalized multiwalled carbon nanotubes/polypropylene nanocomposite bipolar plates for polymer electrolyte membrane fuel cells

Multiwalled carbon nanotubes (MWCNTs) are covalently modified with different molecular weights 400 and 2000 poly(oxyalkylene)-amine bearing the diglycidyl ether of bisphenol A (DGEBA) epoxy (POA400-DGEBA and POA2000-DGEBA) oligomers. The oxidized MWCNTs (MWCNTs-COOH) are converted to the acid chloride-functionalized MWCNTs, followed by the reaction with POA-DGEBAs to prepare the MWCNTs/POA400-DGEBA and MWCNTs/POA2000-DGEBA. FTIR, thermogravimetric analysis (TGA) and high resolution X-ray photoelectron spectra (XPS) reveal that the POA-DGEBAs are covalently attached to the surface of MWCNTs. The morphology of MWCNTs/POA-DGEBA is observed by TEM. The POA400-DGEBA coated on the MWCNTs is thicker and more uniform. However, the coating of POA2000-DGEBA on the MWCNTs shows a worm-like bulk substance and the MWCNT surface is bare. In addition, the flexural strength and the bulk electrical conductivity of the MWCNTs/polypropylene nanocomposite bipolar plates are measured 59% and 505% higher than those of the original composite bipolar plates by adding 8 phr of MWCNTs/POA400-DGEBA. The maximum current density and power density of the single cell test for the nanocomposite bipolar plate with 4 phr MWCNTs/POA400-DGEBA are 1.32 A cm⁻² and 0.533 W cm⁻², respectively. The overall performance confirms the functionalized MWCNTs/polypropylene nanocomposite bipolar plates prepared in this study are suitable for PEMFC application.     

Electrochemical and mechanical behavior of carbon composite bipolar plate for fuel cell

Composite bipolar plates for fuel cells were prepared by a compression molding technique using novolac type phenol formaldehyde resin as a binder and natural graphite, carbon black and carbon fiber as reinforcements. The plates were characterized for electrical conductivity, mechanical strength and corrosion resistance. The flexural strength of the bipolar plate for optimum composition (PF:30%; NG:60%; CB:5%; CF:5%) was 55.28 MPa, with a deflection of 5.2% at mid-span, while the in-plane and through-plane electrical conductivities were 286 and 92 S cm⁻¹, respectively. Corrosion analyses were conducted in normal and rigorous simulated polymer electrolyte membrane fuel cell and alkaline fuel cell environments. The corrosion current density was close to the limit set by the USA Department of Energy. The corrosion current density at the optimum composition was found to be 0.99 μA cm⁻² for polymer electrolyte membrane fuel cell and 17.62 μA cm⁻² for alkaline fuel cell environments.     

Preparation and properties of thin epoxy/compressed expanded graphite composite bipolar plates for proton exchange membrane fuel cells

Although the composite bipolar plates prepared by the method of the vacuum resin impregnation in compressed expanded graphite (CEG) sheets have been applied in the KW-class stacks, there have been few investigations of the preparation and properties of them so far. In this research, the influences of the microstructure on the physical properties of the thin epoxy/CEG composites (the thickness is 1 mm) are investigated for the first time and the optimum preparation conditions are obtained. Results demonstrated that the mechanical property and the impermeability of the composites increases evidently with the resin content changing from 4% to 30%, while the electrical properties keep nearly constant. It can be attributed to the continuous expanded graphite (EG) conductive network of the raw CEG sheet. The epoxy (30 wt.%)/CEG composite is shown to be the optimum composite, displaying in-plane conductivity of 119.8 S cm⁻¹, through-plane resistance of 17.13 mΩ cm², density of 1.95 g cm⁻³, gas permeability of 1.94 × 10⁻⁶ cm³ cm⁻² s⁻¹ and flexural strength of 45.8 MPa. The alcohol scrubbing is the optimum method of surface post-processing. The performance of a single cell with the optimum composite bipolar plates is tested and demonstrated to be outstanding. Above all, the composite prepared by resin vacuum impregnation in the CEG sheet is a promising candidate for bipolar plate materials in PEMFCs.     

Study on the preparation and properties of novolac epoxy/graphite composite bipolar plate for PEMFC

In this study, the graphite/polymer composite bipolar plate was manufactured by a bulk-molding compound process. Low-cost novolac epoxy was chosen to compound with natural graphite and black carbon. The electrical properties and mechanical properties of composite bipolar plate were studied. The aging behavior was characterized according to the changes in property before and after the immersion test. The results show that the composite bipolar plates have good corrosion resistibility in the simulated solution of 0.005 mol L⁻¹ H₂SO₄ + 2 × 10⁻⁶ mol L⁻¹ HF. TGA result shows that the novolac epoxy/NG composite has excellent thermal stability. The optimum processing conditions for preparing composite bipolar plate are: resin content about 15 wt.%; molding pressure 200 MPa; curing temperature 180 °C; graphite particle size −200 mesh. Under the optimum conditions, the composite bipolar plates have been produced, the electrical conductivity can attain to 120 S/cm and flexural strength is higher than 38 MPa.     

Solvent-assisted graphite loading for highly conductive phenolic resin bipolar plates for proton exchange membrane fuel cells

A highly conductive polymer-based bipolar plate is fabricated using phenolic resin and graphite for proton exchange membrane fuel cells (PEMFCs). In order to load graphite fillers up to 90 wt% and minimize the void volume, the wetting properties of the graphite and phenolic resin are key factors for ensuring high electrical conductivity of the bipolar plates through good contact and uniform dispersion of graphite fillers. Since the surface free-energies of the phenolic resin and graphite are significantly different at 107.77 and 43.3 mJ m⁻², respectively, to give a high contact angle of 87.1°, methanol with 19.6 mJ m⁻² of surface energy is incorporated to decrease the contact angle between the matrix and graphite to 11.2°. By adjusting the surface energy of the matrix system, the conductivity of a composite containing 90 wt% of graphite reaches 379 S cm⁻¹. The air permeability of the composite containing 80 wt% of graphite is less than 5 × 10⁻⁶ cm³ cm⁻² s without open pores. The flexural modulus ranges from 6700 to 11000 MPa for graphite loads between 60 and 80 wt%, respectively.     

Development of preform moulding technique using expanded graphite for proton exchange membrane fuel cell bipolar plates

A preform moulding technique using expanded graphite is developed to manufacture composite bipolar plates for proton exchange membrane fuel cells (PEMFCs). The preform is composed of expanded graphite, graphite flake and phenol resin. Preforms utilizing the tangled structure of expanded graphite are easily fabricated at a low pressure of 0.07–0.28 MPa. A pre-curing temperature (100 °C) slightly above the melting point of phenol powders (90 °C) induces moderate curing, but also prevents excessive curing. After the preform is placed in a steel mould, compression moulding is carried out at high pressure (10 MPa) and temperature (150 °C). The fabrication conditions are optimized by checking the electrical conductivity, flexural strength and microstructure of the composite. The optimized electrical conductivity and flexural strength, 250 S cm⁻¹ and 50 MPa, respectively, met the requirements for PEMFC bipolar plates.     

Effects of resin content and preparing conditions on the properties of polyphenylene sulfide resin/graphite composite for bipolar plate

In the paper, a kind of polyphenylene sulfide (PPS) resin/graphite (G) composite for bipolar plate was prepared by using the PPS resin as adhesive and simple hot pressing. The influences of the resin content, the molding temperature and holding time on the conductivity and the bending strength of the PPS/G composite bipolar plate were investigated firstly and then the optimum content and the preparing conditions of the composite were obtained. The experimental results show that the electrical conductivity decreases and the bending strength reveals a serrated variation with increase in PPS resin content; when the holding time is certain, the conductivity decreases and the bending strength increases with the molding temperature increasing. The experimental results further show that the effect of the holding time on the properties of the composite is different at different molding temperatures. The PPS/G composite with 20% PPS resin content has electrical conductivity of 118.9 S cm⁻¹ and bending strength of 52.4 MPa when it molded at 380 °C for 30 min, and has electrical conductivity of 105 S cm⁻¹, bending strength of 55.7 MPa when it molded at 390 °C for 30 min. The properties of the composites can meet the requirements of United States Department of Energy (DOE).     

Performance of a proton exchange membrane fuel cell stack using conductive amorphous carbon-coated 304 stainless steel bipolar plates

In this study, 304 stainless steel (SS) bipolar plates are fabricated by flexible forming process and an amorphous carbon (a-C) film is coated by closed field unbalanced magnetron sputter ion plating (CFUBMSIP). The interfacial contact resistance (ICR), in-plane conductivity and surface energy of the a-C coated 304SS samples are investigated. The initial performance of the single cell with a-C coated bipolar plates is 923.9 mW cm⁻² at a cell voltage of 0.6 V, and the peak power density is 1150.6 mW cm⁻² at a current density of 2573.2 mA cm⁻². Performance comparison experiments between a-C coated and bare 304SS bipolar plates show that the single cell performance is greatly improved by the a-C coating. Lifetime test of the single cell over 200 h and contamination analysis of the tested membrane electrode assemble (MEA) indicate that the a-C coating has excellent chemical stability. A 100 W-class proton exchange membrane fuel cell (PEMFC) short stack with a-C coated bipolar plates is assembled and shows exciting initial performance. The stack also exhibits uniform voltage distribution, good short-term lifetime performance, and high volumetric power density and specific power. Therefore, a-C coated 304SS bipolar plates may be practically applied for commercialization of PEMFC technology.     

Aluminate cement/graphite conductive composite bipolar plate for proton exchange membrane fuel cells

Aluminate cement/graphite conductive composite bipolar plate for proton exchange membrane fuel cells (PEMFC) was prepared by mold pressing at room temperature. The effect of size of graphite particles on the conductivity and the flexural strength of composite bipolar plate were discussed. Resistance to acid corrosion, thermal property and pore size distribution of this composite bipolar plate were also investigated in this paper. The experiment results show that the conductivity and the flexural strength of this composite bipolar plate can be improved by choosing uniform size graphite as conductive fillers. The corrosion current is about 10^−4.5 A cm⁻² from polarization curves of this composite bipolar plate, which shows that this composite bipolar plate is acid corrosion-resistant. Al and Ca ions may leach from this composite bipolar plate after 1 M H₂SO₄ acid corrosion. But Al and Ca ions leaching from this composite bipolar plate are only a little percentage of the total Al and Ca ions content in the composite bipolar plate after acid corrosion at 30 °C. This composite bipolar plate is also thermally stable from room temperature to 400 °C. The large amount of pore in this composite bipolar plate is gel capillary pores because of the hydration and solidification of aluminate cement, which make it possess humidifying function during the PEMFC operating.     

Improved anticorrosion properties and electrical conductivity of 316L stainless steel as bipolar plate for proton exchange membrane fuel cell by lower temperature chromizing treatment

The lower temperature chromizing treatment is developed to modify 316L stainless steel (SS 316L) for the application of bipolar plate in proton exchange membrane fuel cell (PEMFC). The treatment is performed to produce a coating, containing mainly Cr-carbide and Cr-nitride, on the substrate to improve the anticorrosion properties and electrical conductivity between the bipolar plate and carbon paper. Shot peening is used as the pretreatment to produce an activated surface on stainless steel to reduce chromizing temperature. Anticorrosion properties and interfacial contact resistance (ICR) are investigated in this study. Results show that the chromized SS 316L exhibits better corrosion resistance and lower ICR value than those of bare SS 316L. The chromized SS 316L shows the passive current density about 3E−7 A cm⁻² that is about four orders of magnitude lower than that of bare SS 316L. ICR value of the chromized SS 316L is 13 mΩ cm² that is about one-third of bare SS 316L at 200 N cm⁻² compaction forces. Therefore, this study clearly states the performance advantages of using chromized SS 316L by lower temperature chromizing treatment as bipolar plate for PEMFC.     

Improvement of corrosion resistance and electrical conductivity of 304 stainless steel using close field unbalanced magnetron sputtered carbon film

Carbon film has been deposited on 304 stainless steel (SS304) using close field unbalanced magnetron sputter ion plating (CFUBMSIP) to improve the corrosion resistance and electrical conductivity of SS304 acting as bipolar plates for proton exchange membrane fuel cells (PEMFCs). The corrosion resistance, interfacial contact resistance (ICR), surface morphology and contact angle with water of the bare and carbon-coated SS304 are investigated. The carbon-coated SS304 shows good corrosion resistance in the simulated cathode and anode PEMFC environment. The ICR between the carbon-coated SS304 and the carbon paper is 8.28-2.59 mΩ cm² under compaction forces between 75 and 360 N cm⁻². The contact angle of the carbon-coated SS304 with water is 88.6°, which is beneficial to water management in the fuel cell stack. These results indicate that the carbon-coated SS304 exhibits high corrosion resistance, low ICR and hydrophobicity and is a promising candidate for bipolar plates.     

Preparation and properties of high performance nanocomposite bipolar plate for fuel cell

This study aims at developing lightweight and high performance composite bipolar plates for use in polymer electrolyte membrane fuel cells (PEMFCs). The thin polymer composite bipolar plates (the thickness <1.5 mm) containing of vinyl ester resin, graphite powder, organoclay have been fabricated by bulk molding compound (BMC) process. Organoclay was prepared by ionic exchange of montmorillonite (MMT) with three different molecular weight (M_w) of poly(oxypropylene)-backboned diamine intercalating agents. Results indicate that the basal spacing and content of MMT varied with M_w of POP-diamines are critical in determining the resultant mechanical properties for bipolar plates. Flexural strength of MMT composite plates was increased from 30.21 to 45.66 MPa by adding 2 phr of MMT. The flexural strength of the plate was also ca. 38% higher than the pristine graphite plate as the basal spacing of MMT was increased from 1.71 to 5.43 nm. Meanwhile, the unnotched impact strength of the composite plates was increased from 58.11 to 80.21 J m⁻¹. The unnotched impact strength of the plate was ca. 30% higher than that of the original graphite plates as the basal spacing of MMT was increased from 1.71 to 5.43 nm. The limiting oxygen index (LOI) and the UL-94 test revealed that the bipolar plate possesses excellent flame retardant with LOI >50 and UL-94-V0. The thermal decomposition temperature of each MMT composite plate is also higher than 250 °C. In addition, the bulk electrical conductivity of the bipolar plate with different MMT contents and basal spacing of MMT is higher than 100 S cm⁻¹. The corrosion current is less than 10⁻⁷ A cm⁻². Results confirm that the addition of MMT leads to a significant improvement on the performance of the composite bipolar plate.     

A self-pumping and self-breathing micro direct methanol fuel cell with polymer bipolar plates

A passive micro direct methanol fuel cell (DMFC) for reducing volume and parasitic power is designed and fabricated using several integrated technologies. New bipolar plates with tapered channels at the anode and a pillar array at the cathode are first applied to a passive micro-DMFC. The substrate of the bipolar plates made of acrylonitrile butadiene styrene (ABS) is hot embossed with two molds, fabricated by UV-LIGA and micro machining. To make the bipolar plates conductive and hydrophilic, a nickel layer is electroplated on the ABS plates, and three PDDA/PSS bi-layers are self-assembled onto the nickel layer. The bipolar plates are produced using hot embossing, a low cost, highly accurate batch process. A single cell is assembled to verify the self-pumping function, and it can generate a peak power density of 7.4 mW cm⁻² with a 3 M methanol solution. The fuel cell is verified to work in three different orientations. When the fuel cell is placed horizontally, the self-pumping rate is about 0.1-0.15 mL h⁻¹. And the fuel cell can work through self-pumping for 5 h under this condition.