Μm Foil Research Articles

Revisiting the Anodic Stability of Aluminum Current Collectors in High-Voltage Li-Ion Batteries

High-voltage Li-ion batteries are anticipated to play a crucial role in the present transition towards electric vehicles, owing to their high energy density. However, a big challenge is the anodic stability (often referred to as corrosion) of the positive electrodes current collector, aluminum (Al), at potentials > 3.0 V vs. Li+/Li). In this work, we present a systematic study on the corrosion of 12 µm-thick Al foil (©Gränges, Sweden) up to 5.0 V vs. Li+/Li in a series of carbonate electrolytes containing lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl) imide (LiFSI) or lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) salts. The selection of the 12 µm foil was motivated by the need to decrease the mass or volume of the dead weight components (i.e., current collector) to increase the energy density of the battery.The electrochemical behavior was investigated using voltammetric techniques, and the results indicated that the anodic oxidation of the 12 µm Al foil was similar to that of the conventionally used 20 µm-thick Al foil. Notably, the first anodic oxidation scan exhibited a two-step oxidation after 3.5 V vs. Li+/Li, suggesting carbonate solvent oxidation and a liberation of H+ ions attacking the native surface Al2O3 layer followed by oxidation of metallic Al. A passivation was observed on the subsequent scans in 1.0 M LiPF6 solutions due to formation of surface layer of AlF3, as confirmed by X-ray photoelectron spectroscopy (XPS) analyses. [1,2]However, in 1.0 M solutions of the imide salts (i.e., LiFSI or LiTFSI) a continuous anodic oxidation of aluminum was seen between 3.5 and 5.0 V vs. Li+/Li on the first few scans. After this the magnitude of the anodic current decreased significantly. The latter observations can be attributed to formation of soluble Al(TFSI) x or Al(FSI) x complexes [3] and a gradual saturation of the electrolyte. The voltammetric experiments showed that the magnitude of the anodic current increased when increasing the volume of the used imide electrolyte, supporting the saturation hypothesis.Results and analyses regarding the anodic oxidation of Al in a series of carbonate solvents and using different salt concentration, as well as effect of the use of carbon coated Al will also be presented.

Tuned Reactivity at the Lithium Metal–Argyrodite Solid State Electrolyte Interphase

AbstractThin intermetallic Li2Te–LiTe3 bilayer (0.75 µm) derived from 2D tellurene stabilizes the solid electrolyte interphase (SEI) of lithium metal and argyrodite (LPSCl, Li6PS5Cl) solid‐state electrolyte (SSE). Tellurene is loaded onto a standard battery separator and reacted with lithium through single‐pass mechanical rolling, or transferred directly to SSE surface by pressing. State‐of‐the‐art electrochemical performance is achieved, e.g., symmetric cell stable for 300 cycles (1800 h) at 1 mA cm−2 and 3 mAh cm−2 (25% DOD, 60 µm foil). Cryo‐stage focused ion beam (Cryo‐FIB) sectioning and Raman mapping demonstrate that the Li2Te–LiTe3 bilayer impedes SSE decomposition. The unmodified Li–LPSCl interphase is electrochemically unstable with a geometrically heterogeneous reduction decomposition reaction front that extends deep into the SSE. Decomposition drives voiding in Li metal due to its high flux to the reaction front, as well as voiding in the SSE due to the associated volume changes. Analysis of cycled SSE found no evidence for pristine (unreacted) lithium metal filaments/dendrites, implying failure driven by decomposition phases with sufficient electrical conductivity that span electrolyte thickness. DFT calculations clarify thermodynamic stability, interfacial adhesion, and electronic transport properties of interphases, while mesoscale modeling examines interrelations between reaction front heterogeneity (SEI heterogeneity), current distribution, and localized chemo‐mechanical stresses.

Influence of sustainable packaging material and packaging conditions on physicochemical, microbiological, and sensorial properties of cheeses

The aim of this study was to evaluate the influence of different packaging materials [standard foil: BOPP (biaxially oriented polypropylene)/PET (polyester)/PE (polyethylene) for upper layer, and APET (polyethylene terephthalate)/PE for bottom layer; foil 1: PP (polypropylene)/PET/PE/EVOH (ethylene-vinyl alcohol copolymer)/PE upper layer, and PP/PE/EVOH/PE bottom layer; foil 2: PP/PET/PE/EVOH/PE upper layer, and PA (polyamide)/EVOH/PE bottom layer; foil 3: PP/PET/PE upper layer, and PA/EVOH/PE bottom layer; foil 4: PP/PET/PE upper layer, and PA/PE bottom layer; foil 5: PP upper layer, and PP/PP bottom layer] on the quality of 3 different ripening rennet cheeses packed under different modified atmosphere (MAP) conditions as reflected in particular physicochemical, microbiological, and sensorial changes. The changes were monitored during a period of 90 d of storage at 2°C or 8°C. For Gouda cheese, CO2 content of the headspace of the packages was in the range 35% to 45%, whereas for Maasdamer and Sielski Klasyczny cheeses it was 55% to 65%. Three-way ANOVA showed that the foil type influenced the moisture content of Gouda cheese stored for 90 d at 2°C and for Sielski Klasyczny cheese at 8°C, whereas the moisture content was not dependent on MAP conditions during storage. Moreover, the foil type had a significant effect on free fatty acid changes for Gouda and Sielski Klasyczny cheeses stored at 2°C for 90 d. Sensory attributes changed significantly over storage time at 2°C for all studied cheeses as affected by foil type, whereas there was no effect of MAP conditions. In general, the cheeses packed in standard foil and foil 4 were characterized by the highest values of mean sensory attributes. Time was the most significant factor influencing most changes in physicochemical and sensory attributes of cheeses stored at 2°C and 8°C. The storage temperature did not affect the moisture of the samples during storage. In general, we found an increase in the pH value during storage regardless of storage temperature. It was possible to decrease the thickness of the packaging material from initial 103 and 250 µm (standard foil; lid and bottom, respectively) to 98 and 100 µm (foil 4) without affecting sensory attributes of the product.

Microalloying of Continuous Cast Aluminum Strip and Structural Modification Using Plastic Treatment to a 9 μm Foil (Patent no. 39762, P-377/76)

Microalloying of Continuous Cast Aluminum Strip and Structural Modification Using Plastic Treatment to a 9 μm Foil (Patent no. 39762, P-377/76)

Applying optical coherence tomography for weld depth monitoring in remote laser welding of automotive battery tab connectors

This paper addresses in-process monitoring of weld penetration depth (WPD) during remote laser welding of battery tab connectors using optical coherence tomography (OCT). The research aims at studying the impact of welding process parameters on the accuracy of WPD measurements. In general, the highest measurement accuracy is achievable by positioning the OCT measuring beam toward the bottom of the keyhole. However, finding and maintaining the alignment between the OCT measuring beam and the bottom of the keyhole is a challenging task because of the dynamic changes in the size and shape of the keyhole itself. The paper addresses the above challenge by (1) developing welding process parameters for the Al-Cu thin foil lap joint (Al 1050 foil 450 μm and Ni-plated Cu foil 300 μm) using a novel adjustable ring mode (ARM) laser and (2) integrating OCT technology with two beams: one targeting the bottom of the keyhole and another as a reference to the part surface (TwinTec technology). The methodology is underpinned by the “Keyhole Mapping” approach, which helps one to identify the optimal placement of the OCT measuring beam with considerations to both measurement accuracy and stability of the keyhole. Findings indicated that welding with the ARM laser results in a more stable process, reduces fluctuations of the keyhole opening, and, therefore, helps one to improve the measurement accuracy by a factor of 50% (from the average error of 0.22 mm to 0.11 mm). Results further identified that the feasible operating window of the OCT measuring beam, corresponding to the highest measurement accuracy, is below 20 μm in length.

Blue laser welding of multi-layered AISI 316L stainless steel micro-foils

This paper investigates the microstructural and mechanical behaviour of overlap micro-joints produced by a blue laser system with a wavelength of ~450 nm. AISI 316L stainless steel was used to produce assemblies of 20 layers of 25 µm micro-foil welded to a single 200 µm foil. The welding speed was varied from 6.5 m/min to 9.5 m/min in incremental steps of 1.0 m/min whilst the power was kept at a maximum output level of 500 W. The joints were analysed for fusion zone microstructure, crystallographic grain structure, microhardness distribution and lap shear and T-peel strengths. Interface width and penetration depth were used as key quality indicators to characterise the fusion zone microstructure. The welding speed modulation indicated that the penetration depth can be easily controlled during blue laser welding. The mechanical strength was evaluated by performing lap shear and T-peel tests. The results indicated that the blue laser welding can have a considerable impact on weld geometry and joint strength as it can reduce discontinuities in welded regions and generate good mechanical properties. This study demonstrated for the first time that the blue laser can be successfully implemented for multiple stack-up joining of stainless steel.

Effect of Hydrogen Electrosorption on Mechanical and Electronic Properties of Pd80Rh20 Alloy.

The interaction of hydrogen with Pt-group metals and alloys is at the center of research in the fields of electrochemistry, electrocatalysis, hydrogen technologies and fuel cells developed under the Hydrogen Economy. In this work, the material under study was Pd80Rh20 alloy (50 μm foil) subjected to hydrogen electrosorption at potentials corresponding to formation of α, α-β and β phase in 0.1 M H2SO4 at 25 °C. The total amount of hydrogen adsorbed at the surface and absorbed in octahedral interstitial positions of fcc Pd80Rh20 alloy, was determined from the oxidation charges. The H/(Pd+Rh) was 0.002, 0.4 and 0.8 for α, α-β, and β Pd80Rh20H, respectively. Microindentation hardness testing and nanoindentation showed weakening of mechanical properties of the Pd80Rh20 alloy after hydrogen electrosorption due to internal stresses. Decrease of work function with increasing amount of hydrogen absorbed occurred due to the surface roughness changes and the presence of electropositive hydrogen atoms absorbed in the crystal lattice responsible for the dipole interaction. The detailed mechanism of hydrogen absorption/diffusion in the Pd80Rh20 alloy structure is discussed. The obtained results give a new insight into the relationship between the amount of absorbed hydrogen and mechanical and electronic properties of the Pd80Rh20 alloy at the micro- and nanoscale.

The Effect of Rapid Photon Treatment of the PdCu Solid Solution Foil of Near-Equiatomic Composition

β $$ \rightleftarrows $$ α transformations in a thin ~4 µm foil of the PdCu solid solution have been studied by X-ray powder diffraction and measurement of electrical resistance in heating–cooling cycles during heat treatment or rapid photon treatment by radiation of high-power pulsed xenon lamps. It has been found that a single rapid photon treatment for 0.3 s (the radiation energy dose delivered to the sample is 10 J cm–2) leads to a complete disordering of the solid solution at a rate 400 times higher than in that achieved under heat treatment conditions (heating rate of 15 K min–1).

Sn‐Alloy Foil Electrode with Mechanical Prelithiation: Full‐Cell Performance up to 200 Cycles

AbstractSelf‐supporting Sn foil is a promising high‐volumetric‐capacity anode for lithium ion batteries (LIBs), but it suffers from low initial Coulombic efficiency (ICE). Here, mechanical prelithiation is adopted to improve ICE, and it is found that Sn foils with coarser grains are prone to cause electrode damage. To mitigate damage and prepare thinner lithiated electrodes, 3Ag0.5Cu96.5Sn foil is used that has more refined grains (5–10 µm) instead of Sn (50–100 µm), where the abundant grain boundaries (GBs) offer more sliding systems to release stress and reduce deep fractures. Thus, the thickness of Lix3Ag0.5Cu96.5Sn can be reduced to 50 µm, compared to 100 µm LixSn. When the foils contact open air, the Sn‐Li‐O(H) products are more stable than Li‐O(H), thus Lix3Ag0.5Cu96.5Sn shows outstanding air stability. The as‐prepared 50 µm foil anode achieves stable 200 cycles in LiFePO4//Lix3Ag0.5Cu96.5Sn full cell (≈2.65 mAh cm−2) and the capacity retention is 95%. Even at 5C, the capacity of Lix3Ag0.5Cu96.5Sn is still up to ≈1.8 mAh cm−2. The cycle life of NCM523//Lix3Ag0.5Cu96.5Sn full cell exceeds that of NCM523//Li. Furthermore, 70 µm Lix3Ag0.5Cu96.5Sn is used as double‐sided anode for a 3 cm × 2.8 cm pouch cell and its actual volumetric capacity density is 674 mAh cm−3 after 50 cycles.

Zn-Sn Interdigitated Eutectic Alloy Anodes with High Volumetric Capacity for Lithium-Ion Batteries

Summary Zn-Sn interdigitated eutectic alloy (IdEA) foils are highly promising anodes for lithium-ion batteries. Synthesized via severe plastic deformation, a two-phase alloy is converted into a nanostructured foil composed of tin domains distributed throughout an electrically conductive zinc matrix. In addition to providing mechanical integrity, uncycled capacity in the zinc matrix eliminates the lithium-plating risk. These monolithic foil anodes offer an electrode-level volumetric capacity approximately double that of graphite (797 mA h cm−3), with a highly promising formation loss of

311. Preliminary results of the production of Ga-68 with biomedical cyclotron by liquid target

Purpose The aim of this work was to evaluate the feasibility of production of 68Ga via the 68Zn(p,n)68Ga reaction by proton irradiation of enriched zinc nitrate solution using a biomedical cyclotron, an alternative method to the current production through the 68Ge/68Ga generators. Methods The target material was prepared by dissolving metallic 68Zn (enrichment of 99.26%) in HNO3 6 N and then diluting it with HNO3 0.2 N to obtain a 1.7 M solution of 68Zn(NO3)2 [1] . Using the cross-section data (EXFOR database) and the proton stopping power (SRIM software), the 68Ga saturation yield and its impurities were estimated. Irradiation tests were performed using the GE PETtrace cyclotron, located at our Institution. A liquid target was used, with a 25 μm foil of Havar® and a 250 μm foil of Niobium, employed to obtain proper selection of entrance beam energy, to degrade the energy of the beam to 12 MeV in order to minimize the production of 67Ga through the 68Zn(p,2n)67Ga reaction. The modification of the target also allowed us to improve resistance of the foil to acidity of the target material. Irradiations were carried out for 32 ± 1 min at 47 ± 2 μA. The product’s activity was measured using an activity meter calibrated with a standard of 68Ge traceable to NIST, while radionuclidic purity was evaluated by using gamma-ray spectrometry with an HPGe detector. Results The gamma-spectra of the irradiated samples showed the presence of different isotopes of Ga, Cu and Co, as predicted by the theoretical estimates. Radionuclidic purity is within the limits of EU Pharmacopeia up to 3 h after end of bombardment. Separation and recovery up to a yield of 90 ± 9% was obtained. Conclusions In summary, although optimizations and further advances are necessary, the results obtained are very promising and demonstrate the feasibility to produce sufficient activity of 68Ga in cyclotron as a competitive alternative to the 68Ge/68Ga generators.

Effect of hydrogen electrosorption on corrosion resistance of Pd80Rh20 alloy in sulfuric acid: EIS and LEIS study

Corrosion behavior of the Pd80Rh20 alloy (50 μm foil) was studied in 0.1 M H2SO4 before and after hydrogen electrosorption at potentials corresponding to formation of α, α-β and β phase. Mechanism and kinetics of the corrosion process was studied using EIS and LEIS combined with potentiodynamic measurements and SEM. Hydrogen electrosorption influenced the decrease of the corrosion resistance of the Pd80Rh20 electrode. The local impedance was lower than the bulk impedance determined by EIS due to the presence of internal stresses and microcracks. The obtained results give a new insight into the relationship between the quantitative description of the corrosion resistance of the Pd80Rh20 alloy and the amount of absorbed hydrogen.

Enhanced laser proton acceleration by target ablation on a femtosecond laser system

Proton acceleration during the interaction of an ultraintense (6 × 1019 W/cm2) femtosecond (fs) laser pulse with a thin (2.5 μm) foil target pre-ablated by a picosecond (ps) pulse is experimentally and numerically investigated. Enhancements in both proton cut-off energy and charge are observed with the target ablation due to a large number of energetic electrons generated from the preformed preplasma in front of the target. The enhanced proton beams are successfully collected at 4–9 MeV with ±4% energy spread and then transported to the irradiating platform. The results show that for the interaction between fs laser pulse and μm-thickness target, proton energy and charge can be enhanced by target ablation using a ps laser pulse, which is valuable for application like cancer radiotherapy.

Study of the hydrogen absorption/diffusion in Pd80Rh20 alloy in acidic solution

Hydrogen absorption/diffusion into Pd80Rh20 alloy (50 μm foil) was studied using cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy in 0.1 M H2SO4 at 25 °C in the absence and presence of crystal violet. The double layer capacitance, charge transfer resistance, diffusion coefficient and mass transfer coefficient of hydrogen were determined. The mechanism of hydrogen absorption was discussed. Hydrogen adsorption inhibits the kinetics of hydrogen absorption and, in the presence of crystal violet, it proceeds much faster. At more positive potentials crystal violet is probably desorbed and the kinetics of absorption in the absence and in the presence of crystal violet proceeds with similar rate.

Tailoring the Surface Morphology and Microstructure of Electrodeposited Copper Foil with Organic Additives

Copper foil manufactured by high-speed electrochemical deposition (ED) is an essential material for its extensive applications such as the negative current collector for lithium-ion batteries (LIBs) or building up the designed connection pattern on the printed circuit boards (PCBs). Thus, producing copper foil with optimal quality and machinability depending on the end products is necessary. For example, the thickness of Cu foils for LIBs should be thin (< 10 µm) to reduce the volume and weight of batteries but the mechanical properties should remain strong enough to go through the roll-to-roll manufacturing process without fracture. In addition, the surface roughness on both sides should be identically smooth and glossy to provide the coating carbon materials with acceptable wetability and adhesion. On the other hand, Cu foils for the fifth generation (5G) high-frequency wireless devices should be exceedingly smooth because the skin depth of copper caused by the so-called skin effect is merely 0.266 µm when the transmitting frequency of signals is up to 60 GHz. Thus, a great majority of electric current passing through the conductor will flow extremely near the surface. Under such circumstances, coarse surface roughness has a significant detrimental effect on the signal loss of wireless communication devices, and consequently, the surface morphology and mechanical properties of copper foils should be further improved in order to meet the requirements for the next generation electronic devices. The microstructure of copper fabricated by ED depends highly on plating parameters, including current density, convection rate of the electrolyte, pulsed/direct current deposition, or using appropriate organic additives to ameliorate the nucleation behavior of Cu from cupric ions. Manufacturing of ED copper foils ought to operate with very high current density and high temperature to promote the yield rate for mass production, and the gelatin-based additive has been used for a long time. However, grain structure and surface roughness are coarse and mechanical properties are merely acceptable with around 250 MPa tensile strength and a 4% elongation rate for a normal 18 µm foil. In this work, we demonstrate the copper foil fabricated by high-speed electrodeposition with a current density of 450 mA/cm2 (average growth rate > 150 nm/s) from a 54oC bath, which meets the required yield rate for genuine mass-production, and tailoring the microstructure of copper with selective additives. The surface morphology of the foil facing the electrolyte side is smooth by our designed additives, and surface roughness values, Ra and Rq, are less than 100 nm, which are as smooth as foils manufactured via rolling process. In addition, the structure of copper is further tuned by a specific additive, and the grain size of copper is getting smaller as the concentration of this additive is increased. When the concentration of this additive is up to 800 ppm, the average grain size of copper is shrunk from 3 µm to 0.3 µm, and extremely unique copper texture with nearly single (220) orientation is constructed. Owing to such delicate microstructure, considerable improvement in mechanical properties with more than 40 % increase in tensile strength and 4 times increase in the elongation rate compared to the conventional gelatin-based copper foil is achieved. The surface morphology and structure of copper foil are properly characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), electron back-scattered diffraction (EBSD), transmission electron microscopy (TEM) and tensile testing machine, and the applied additive to tailor the structure of copper will be clearly revealed and discussed. Finally, a novel and commercially realizable scheme to fabricate copper foil with ultra smooth surface morphology and ductile mechanical properties by high-speed ED is proposed.

Observation of impact of eddy current on laser targets in a strong fast rising magnetic field

Pulsed power generators are capable of producing strong magnetic fields. Foil laser targets for high intensity interactions with matter were characterized in a strong magnetic field produced by different types of loads. Longitudinal magnetic fields generated by coil loads were measured by Faraday rotation of the polarization plane of laser beams in a small glass sample at two wavelengths. Magnetic fields of 0.8–1.5 MG were measured in different coil loads at 1 MA current. For the first time, the impact of eddy current generated by the fast rising magnetic field with dB/dt = 109 T/s was observed in Al laser targets using shadowgraphy and interferometry. Material of the Al 10 μm foil target expanded from both sides at 0.1–0.2 mm. This effect was not observed in dielectric targets. The impact of eddy current on targets is important for designing experiments for laser plasma interactions in strong magnetic fields.

Comprehensive studies on microstructural, electronic, thermo-optical, mechanical and tribological behavious of vacuum heat treated ultra thin CP Ti foils

Present study reports the effect of vacuum (10−5 mbar) heat treatment (300 °C–900 °C) on the microstructural, electronic, thermo-optical, mechanical and tribological properties of commercially pure (CP) titanium (Ti) ultra thin (75 µm) foil. Phase analysis and surface morphology of the as-received and vacuum heat treated Ti foil samples were investigated by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and profilometry techniques. X-ray photoelectron spectroscopy (XPS) was employed to understand the electronic structure of the Ti foil surfaces. The solar absorptance (αs), solar reflectance (ρs) and IR emittance (εir) of the as-received and vacuum heat treated Ti foil samples were evaluated. For vacuum heat treatment temperatures above 700 °C these properties were significantly altered. Nanoindentation study was carried out to evaluate hardness and elastic modulus while single pass scratch tests were performed to understand the tribological behaviour of the as-received and vacuum heat treated Ti foil samples. Further, yield strength and elongation of the as-received and vacuum heat treated Ti foil samples were measured from the tensile tests. Based on the experimental results it is suggested that the nanoindentation response of the as-received and vacuum heat treated Ti foil samples can be significantly affected by presence or absence of residual stress and pile-up around the nanoindents. Moreover, the results implied that possibly the formation of hard and brittle TiC phase during vacuum heat treatment temperature at and above 700 °C had influenced the thermo-optical, mechanical and tribological properties of the thin Ti foils.

Three-dimensional microscopy of deuterium in tungsten

The hydrogen isotope retention in tungsten is an important issue for fusion devices. In this paper we study the possibility of using a μm-focused deuterium beam in order to quantify deuterium distributions in microscopic dimensions. Due to the lack of cross-section data for deuteron–deuteron-scattering (dd-scattering) a validated reference sample is needed. For this purpose we used a 15 μm thick aluminum foil covered by a-C:D-layers that have been deposited in a CD4 plasma discharge from both sides. At the SNAKE facility of the Munich tandem accelerator we already established a three-dimensional microscopy of hydrogen using protons within an energy range between 17 and 25 MeV. Now, we have tested the possibility for deuteron microscopy. As a first application we analyzed a 25 μm foil implanted with 2.0 × 1020 atom cm−2 deuterons.

Polymer-based microfluidic device for measuring membrane protein activities

Functional assays of membrane proteins are becoming increasingly important, both in research and drug discovery applications. The majority of current assays use the patch-clamp technology to measure the activity of ion channels which are over-expressed in cells. In future, in vitro assay systems will be available, which use reconstituted membrane proteins in free-standing lipid bilayers suspended in nano- or micrometer-sized pores. Such functional assays require (1) expression, purification and reconstitution of the membrane protein of interest, (2) a reliable method for lipid bilayer formation and membrane protein integration, and (3) a sensitive detection system. For practical applications, especially for automation, the reliable and controllable transport of fluids is essential. In order to achieve a stable free-standing lipid bilayer, a pore diameter in the micro- to nanometer range is essential. Novel microfluidic devices were developed by bonding a thick (300 μm) polyether ether ketone foil, bearing a channel structure, to a thin (12 μm) foil with a micropore of about 10 μm diameter and then utilized for the formation of stable, free-standing lipid bilayers within the pore. A bacterial voltage-gated potassium channel is integrated therein by fusion and the ion channel activity detected by voltage clamp.

Diffusion driven optofluidic dye lasers encapsulated into polymer chips

Lab-on-a-chip systems made of polymers are promising for the integration of active optical elements, enabling e.g. on-chip excitation of fluorescent markers or spectroscopy. In this work we present diffusion operation of tunable optofluidic dye lasers in a polymer foil. We demonstrate that these first order distributed feedback lasers can be operated for more than 90 min at a pulse repetition rate of 2 Hz without fluidic pumping. Ultra-high output pulse energies of more than 10 μJ and laser thresholds of 2 μJ are achieved for resonator lengths of 3 mm. By introducing comparatively large on-chip dye solution reservoirs, the required exchange of dye molecules is accomplished solely by diffusion. Polymer chips the size of a microscope cover slip (18 × 18 mm(2)) were fabricated in batches on a wafer using a commercially available polymer (TOPAS(®) Cyclic Olefin Copolymer). Thermal imprinting of micro- and nanoscale structures into 100 μm foils simultaneously defines photonic resonators, liquid-core waveguides, and fluidic reservoirs. Subsequently, the fluidic structures are sealed with another 220 μm foil by thermal bonding. Tunability of laser output wavelengths over a spectral range of 24 nm on a single chip is accomplished by varying the laser grating period in steps of 2 nm. Low-cost manufacturing suitable for mass production, wide laser tunability, ultra-high output pulse energies, and long operation times without external fluidic pumping make these on-chip lasers suitable for a wide range of lab-on-a-chip applications, e.g. on-chip spectroscopy, biosensing, excitation of fluorescent markers, or surface enhanced Raman spectroscopy (SERS).