Direct Laser Interference Patterning(DLIP)is used to texture current collector foils in a roll-to-roll process using a high-power picosecond pulsed laser system operating at either fundamental wavelength of 1064 nm or...Direct Laser Interference Patterning(DLIP)is used to texture current collector foils in a roll-to-roll process using a high-power picosecond pulsed laser system operating at either fundamental wavelength of 1064 nm or 2nd harmonic of 532 nm.The raw beam having a diameter of 3 mm@1/e^(2) is shaped into an elongated top-hat intensity profile using a diffractive so-called FBS■-L element and cylindrical telescopes.The shaped beam is split into its diffraction orders,where the two first orders are parallelized and guided into a galvanometer scanner.The deflected beams inside the scan head are recombined with an F-theta objective on the working position generating the interference pattern.The DLIP spot has a line-like interference pattern with about 15μm spatial period.Laser fluences of up to 8 J cm^(-2) were achieved using a maximum pulse energy of 0.6 mJ.Furthermore,an in-house built roll-to-roll machine was developed.Using this setup,aluminum and copper foil of 20μm and 9μm thickness,respectively,could be processed.Subsequently to current collector structuring coating of composite electrode material took place.In case of lithium nickel manganese cobalt oxide(NMC 622)cathode deposited onto textured aluminum current collector,an increased specific discharge capacity could be achieved at a C-rate of 1℃.For the silicon/graphite anode material deposited onto textured copper current collector,an improved rate capability at all C-rates between C/10 and 5℃ was achieved.The rate capability was increased up to 100%compared to reference material.At C-rates between C/2 and 2℃,the specific discharge capacity was increased to 200 mAh g^(-1),while the reference electrodes with untextured current collector foils provided a specific discharge capacity of 100 m Ah g^(-1),showing the potential of the DLIP technology for cost-effective production of battery cells with increased cycle lifetime.展开更多
The lithium-sulfur(Li-S)technology is the most promising candidate for next-generation batteries due to its high theoretical specific energy and steady progress for applications requiring lightweight batteries such as...The lithium-sulfur(Li-S)technology is the most promising candidate for next-generation batteries due to its high theoretical specific energy and steady progress for applications requiring lightweight batteries such as aviation or heavy electric vehicles.For these applications,however,the rate capability of Li-S cells requires significant improvement.Advanced electrolyte formulations in Li-S batteries enable new pathways for cell development and adjustment of all components.However,their rate capability at pouch cell level is often neither evaluated nor compared to state of the art(SOTA)LiTFSI/dimethoxyethane/dioxolane(LITFSI:lithium-bis(trifluoromethylsulfonyl)imide)electrolyte.Herein,the combination of the sparingly polysulfide(PS)solvating hexylmethylether/1,2-dimethoxyethane(HME/DME)electrolyte and highly conductive carbon nanotube Buckypaper(CNT-BP)with low porosity was evaluated in both coin and pouch cells and compared to dimethoxyethane/dioxolane reference electrolyte.An advanced sulfur transfer melt infiltration was employed for cathode production with CNT-BP.The Li+ion coordination in the HME/DME electrolyte was investigated by nuclear magnetic resonance(NMR)and Raman spectroscopy.Additionally,ionic conductivity and viscosity was investigated for the pristine electrolyte and a polysulfide-statured solution.Both electrolytes,DME/DOL-1/1(DOL:1,3-dioxolane)and HME/DME-8/2,are then combined with CNT-BP and transferred to multi-layered pouch cells.This study reveals that the ionic conductivity of the electrolyte increases drastically over state of(dis)charge especially for DME/DOL electrolyte and lean electrolyte regime leading to a better rate capability for the sparingly polysulfide solvating electrolyte.The evaluation in prototype cells is an important step towards bespoke adaption of Li-S batteries for practical applications.展开更多
To meet the surging needs in energy efficiency and eco-friendly lubricants,a novel superlubricious technology using a vegetable oil and ceramic materials is proposed.By coupling different hydrogen-free amorphous carbo...To meet the surging needs in energy efficiency and eco-friendly lubricants,a novel superlubricious technology using a vegetable oil and ceramic materials is proposed.By coupling different hydrogen-free amorphous carbon coatings with varying fraction of sp^(2) and sp^(3) hybridized carbon in presence of a commercially available silicon nitride bulk ceramic,castor oil provides superlubricity although the liquid vegetable oil film in the contact is only a few nanometres thick at most.Besides a partial liquid film possibly separating surfaces in contact,local tribochemical reactions between asperities are essential to maintain superlubricity at low speeds.High local pressure activates chemical degradation of castor oil generating graphitic/graphenic-like species on top of asperities,thus helping both the chemical polishing of surface and its chemical passivation by H and OH species.Particularly,the formation of the formation of–(CH_(2)–CH_(2))n–noligomers have been evidenced to have a major role in the friction reduction.Computer simulation unveils that formation of chemical degradation products of castor oil on friction surfaces are favoured by the quantity of sp^(2)-hybridized carbon atoms in the amorphous carbon structure.Hence,tuning sp^(2)-carbon content in hydrogen-free amorphous carbon,in particular,on the top layers of the coating,provides an alternative way to control superlubricity achieved with castor oil and other selected green lubricants.展开更多
基金funded by the German Federal Ministry of Education and Research(BMBF),project NextGen-3DBat,Grant Number 03XP0198Fby the Fraunhofer Cluster of Excellence Advanced Photon Sources(CAPS)。
文摘Direct Laser Interference Patterning(DLIP)is used to texture current collector foils in a roll-to-roll process using a high-power picosecond pulsed laser system operating at either fundamental wavelength of 1064 nm or 2nd harmonic of 532 nm.The raw beam having a diameter of 3 mm@1/e^(2) is shaped into an elongated top-hat intensity profile using a diffractive so-called FBS■-L element and cylindrical telescopes.The shaped beam is split into its diffraction orders,where the two first orders are parallelized and guided into a galvanometer scanner.The deflected beams inside the scan head are recombined with an F-theta objective on the working position generating the interference pattern.The DLIP spot has a line-like interference pattern with about 15μm spatial period.Laser fluences of up to 8 J cm^(-2) were achieved using a maximum pulse energy of 0.6 mJ.Furthermore,an in-house built roll-to-roll machine was developed.Using this setup,aluminum and copper foil of 20μm and 9μm thickness,respectively,could be processed.Subsequently to current collector structuring coating of composite electrode material took place.In case of lithium nickel manganese cobalt oxide(NMC 622)cathode deposited onto textured aluminum current collector,an increased specific discharge capacity could be achieved at a C-rate of 1℃.For the silicon/graphite anode material deposited onto textured copper current collector,an improved rate capability at all C-rates between C/10 and 5℃ was achieved.The rate capability was increased up to 100%compared to reference material.At C-rates between C/2 and 2℃,the specific discharge capacity was increased to 200 mAh g^(-1),while the reference electrodes with untextured current collector foils provided a specific discharge capacity of 100 m Ah g^(-1),showing the potential of the DLIP technology for cost-effective production of battery cells with increased cycle lifetime.
基金financed by the German Ministry of Education and Research(BMBF)in the project“HiPoLiS”(No.03XP0178A).
文摘The lithium-sulfur(Li-S)technology is the most promising candidate for next-generation batteries due to its high theoretical specific energy and steady progress for applications requiring lightweight batteries such as aviation or heavy electric vehicles.For these applications,however,the rate capability of Li-S cells requires significant improvement.Advanced electrolyte formulations in Li-S batteries enable new pathways for cell development and adjustment of all components.However,their rate capability at pouch cell level is often neither evaluated nor compared to state of the art(SOTA)LiTFSI/dimethoxyethane/dioxolane(LITFSI:lithium-bis(trifluoromethylsulfonyl)imide)electrolyte.Herein,the combination of the sparingly polysulfide(PS)solvating hexylmethylether/1,2-dimethoxyethane(HME/DME)electrolyte and highly conductive carbon nanotube Buckypaper(CNT-BP)with low porosity was evaluated in both coin and pouch cells and compared to dimethoxyethane/dioxolane reference electrolyte.An advanced sulfur transfer melt infiltration was employed for cathode production with CNT-BP.The Li+ion coordination in the HME/DME electrolyte was investigated by nuclear magnetic resonance(NMR)and Raman spectroscopy.Additionally,ionic conductivity and viscosity was investigated for the pristine electrolyte and a polysulfide-statured solution.Both electrolytes,DME/DOL-1/1(DOL:1,3-dioxolane)and HME/DME-8/2,are then combined with CNT-BP and transferred to multi-layered pouch cells.This study reveals that the ionic conductivity of the electrolyte increases drastically over state of(dis)charge especially for DME/DOL electrolyte and lean electrolyte regime leading to a better rate capability for the sparingly polysulfide solvating electrolyte.The evaluation in prototype cells is an important step towards bespoke adaption of Li-S batteries for practical applications.
基金This research is supported by TOTAL,Solaize Research Center and Federal Ministry of Economic Affairs and Energy Germany(BMWi)within project CHEOPS3(Funding number 03ET1286B).
文摘To meet the surging needs in energy efficiency and eco-friendly lubricants,a novel superlubricious technology using a vegetable oil and ceramic materials is proposed.By coupling different hydrogen-free amorphous carbon coatings with varying fraction of sp^(2) and sp^(3) hybridized carbon in presence of a commercially available silicon nitride bulk ceramic,castor oil provides superlubricity although the liquid vegetable oil film in the contact is only a few nanometres thick at most.Besides a partial liquid film possibly separating surfaces in contact,local tribochemical reactions between asperities are essential to maintain superlubricity at low speeds.High local pressure activates chemical degradation of castor oil generating graphitic/graphenic-like species on top of asperities,thus helping both the chemical polishing of surface and its chemical passivation by H and OH species.Particularly,the formation of the formation of–(CH_(2)–CH_(2))n–noligomers have been evidenced to have a major role in the friction reduction.Computer simulation unveils that formation of chemical degradation products of castor oil on friction surfaces are favoured by the quantity of sp^(2)-hybridized carbon atoms in the amorphous carbon structure.Hence,tuning sp^(2)-carbon content in hydrogen-free amorphous carbon,in particular,on the top layers of the coating,provides an alternative way to control superlubricity achieved with castor oil and other selected green lubricants.