@article{MeiKochovskiRoaetal.2019, author = {Mei, Shilin and Kochovski, Zdravko and Roa, Rafael and Gu, Sasa and Xu, Xiaohui and Yu, Hongtao and Dzubiella, Joachim and Ballauff, Matthias and Lu, Yan}, title = {Enhanced Catalytic Activity of Gold@Polydopamine Nanoreactors with Multi-compartment Structure Under NIR Irradiation}, series = {Nano-Micro Letters}, volume = {11}, journal = {Nano-Micro Letters}, number = {1}, publisher = {Shanghai JIAO TONG univ press}, address = {Shanghai}, issn = {2311-6706}, doi = {10.1007/s40820-019-0314-9}, pages = {16}, year = {2019}, abstract = {Photothermal conversion (PTC) nanostructures have great potential for applications in many fields, and therefore, they have attracted tremendous attention. However, the construction of a PTC nanoreactor with multi-compartment structure to achieve the combination of unique chemical properties and structural feature is still challenging due to the synthetic difficulties. Herein, we designed and synthesized a catalytically active, PTC gold (Au)@polydopamine (PDA) nanoreactor driven by infrared irradiation using assembled PS-b-P2VP nanosphere as soft template. The particles exhibit multi-compartment structure which is revealed by 3D electron tomography characterization technique. They feature permeable shells with tunable shell thickness. Full kinetics for the reduction reaction of 4-nitrophenol has been investigated using these particles as nanoreactors and compared with other reported systems. Notably, a remarkable acceleration of the catalytic reaction upon near-infrared irradiation is demonstrated, which reveals for the first time the importance of the synergistic effect of photothermal conversion and complex inner structure to the kinetics of the catalytic reduction. The ease of synthesis and fresh insights into catalysis will promote a new platform for novel nanoreactor studies.}, language = {en} } @article{XuAngiolettiUbertiLuetal.2018, author = {Xu, Xiao and Angioletti-Uberti, Stefano and Lu, Yan and Dzubiella, Joachim and Ballauff, Matthias}, title = {Interaction of Proteins with Polyelectrolytes}, series = {Langmuir}, volume = {35}, journal = {Langmuir}, number = {16}, publisher = {American Chemical Society}, address = {Washington}, issn = {0743-7463}, doi = {10.1021/acs.langmuir.8b01802}, pages = {5373 -- 5391}, year = {2018}, abstract = {We discuss recent investigations of the interaction of polyelectrolytes with proteins. In particular, we review our recent studies on the interaction of simple proteins such as human serum albumin (HSA) and lysozyme with linear polyelectrolytes, charged dendrimers, charged networks, and polyelectrolyte brushes. In all cases discussed here, we combined experimental work with molecular dynamics (MD) simulations and mean-field theories. In particular, isothermal titration calorimetry (ITC) has been employed to obtain the respective binding constants K-b and the Gibbs free energy of binding. MD simulations with explicit counterions but implicit water demonstrate that counterion release is the main driving force for the binding of proteins to strongly charged polyelectrolytes: patches of positive charges located on the surface of the protein become multivalent counterions of the polyelectrolyte, thereby releasing a number of counterions condensed on the polyelectrolyte. The binding Gibbs free energy due to counterion release is predicted to scale with the logarithm of the salt concentration in the system, which is verified by both simulations and experiment. In several cases, namely, for the interaction of proteins with linear polyelectrolytes and highly charged hydrophilic dendrimers, the binding constant could be calculated from simulations to very good approximation. This finding demonstrated that in these cases explicit hydration effects do not contribute to the Gibbs free energy of binding. The Gibbs free energy can also be used to predict the kinetics of protein uptake by microgels for a given system by applying dynamic density functional theory. The entire discussion demonstrates that the direct comparison of theory with experiments can lead to a full understanding of the interaction of proteins with charged polymers. Possible implications for applications, such as drug design, are discussed.}, language = {en} } @article{QuanHaerkXuetal.2021, author = {Quan, Ting and Haerk, Eneli and Xu, Yaolin and Ahmet, Ibbi and H{\"o}hn, Christian and Mei, Shilin and Lu, Yan}, title = {Unveiling the formation of solid electrolyte interphase and its temperature dependence in "Water-in-Salt" supercapacitors}, series = {ACS applied materials \& interfaces}, volume = {13}, journal = {ACS applied materials \& interfaces}, number = {3}, publisher = {American Chemical Society}, address = {Washington}, issn = {1944-8244}, doi = {10.1021/acsami.0c19506}, pages = {3979 -- 3990}, year = {2021}, abstract = {"Water-in-salt" (WIS) electrolytes have emerged as an excellent superconcentrated ionic medium for high-power energy storage systems such as supercapacitors due to their extended working potential compared to the conventional dilute aqueous electrolyte. In this work, we have investigated the performance of WIS supercapacitors using hollow carbon nanoplates as electrodes and compared it to that based on the conventional "salt-in-water" electrolytes. Moreover, the potentiostatic electrochemical impedance spectroscopy has been employed to provide an insightful look into the charge transport properties, which also, for the first time, reveals the formation of a solid-electrolyte interphase (SEI and their temperature-dependent impedance for charge transfer and adsorption. Furthermore, the effect of temperature on the electrochemical performance of the WIS supercapacitors in the temperature range from 15 to 60 degrees C has been studied, which presents a gravimetric capacitance of 128 F g(-1) and a volumetric capacitance of 197.12 F cm(-3) at 55 degrees C compared to 87.5 F g(-1) and 134.75 F cm(-3) at 15 degrees C. The in-depth understanding about the formation of SEI layer and the electrochemical performance at different temperatures for WIS supercapacitors will assist the efforts toward designing better aqueous electrolytes for supercapacitors.}, language = {en} } @article{XieJouiniMeietal.2022, author = {Xie, Dongjiu and Jouini, Oumeima and Mei, Shilin and Quan, Ting and Xu, Yaolin and Kochovski, Zdravko and Lu, Yan}, title = {Spherical polyelectrolyte brushes templated hollow C@MnO nanospheres as sulfur host materials for Li-S batteries}, series = {ChemNanoMat : Chemistry of Nanomaterials for Energy, Biology and More}, volume = {8}, journal = {ChemNanoMat : Chemistry of Nanomaterials for Energy, Biology and More}, number = {4}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {2199-692X}, doi = {10.1002/cnma.202100455}, pages = {8}, year = {2022}, abstract = {Li-S battery has been considered as the next-generation energy storage device, which still suffers from the shuttle effect of lithium polysulfides (LiPSs). In this work, mesoporous hollow carbon-coated MnO nanospheres (C@MnO) have been designed and synthesized using spherical polyelectrolyte brushes (SPB) as template, KMnO4 as MnO precursor, and polydopamine as carbon source to improve the electrochemical performance of Li-S battery. The hollow C@MnO nanospheres enable the combination of physical confinement and chemical adsorption of the LiPSs. The thin carbon coating layer can provide good electrical conductivity and additional physical confinement to polysulfides. Moreover, the encapsulated MnO inside the carbon shell exhibits strong chemical adsorption to polysulfides. The constructed C@MnO/S cathode shows the discharge capacity of 1026 mAh g(-1) at 0.1 C with 79\% capacity retention after 80 cycles. The synthesized hollow C@MnO nanoparticles can work as highly efficient sulfur host materials, providing an effective solution to suppress the shuttle effect in Li-S battery.}, language = {en} } @article{XieXuWangetal.2022, author = {Xie, Dongjiu and Xu, Yaolin and Wang, Yonglei and Pan, Xuefeng and H{\"a}rk, Eneli and Kochovski, Zdravko and Eljarrat, Alberto and M{\"u}ller, Johannes and Koch, Christoph T. and Yuan, Jiayin and Lu, Yan}, title = {Poly(ionic liquid) nanovesicle-templated carbon nanocapsules functionalized with uniform iron nitride nanoparticles as catalytic sulfur host for Li-S batteries}, series = {ACS nano}, volume = {16}, journal = {ACS nano}, number = {7}, publisher = {American Chemical Society}, address = {Washington}, issn = {1936-0851}, doi = {10.1021/acsnano.2c01992}, pages = {10554 -- 10565}, year = {2022}, abstract = {Poly(ionic liquid)s (PIL) are common precursors for heteroatom-doped carbon materials. Despite a relatively higher carbonization yield, the PIL-to-carbon conversion process faces challenges in preserving morphological and structural motifs on the nanoscale. Assisted by a thin polydopamine coating route and ion exchange, imidazoliumbased PIL nanovesicles were successfully applied in morphology-maintaining carbonization to prepare carbon composite nanocapsules. Extending this strategy further to their composites, we demonstrate the synthesis of carbon composite nanocapsules functionalized with iron nitride nanoparticles of an ultrafine, uniform size of 3-5 nm (termed "FexN@C "). Due to its unique nanostructure, the sulfur-loaded FexN@C electrode was tested to efficiently mitigate the notorious shuttle effect of lithium polysulfides (LiPSs) in Li-S batteries. The cavity of the carbon nanocapsules was spotted to better the loading content of sulfur. The well-dispersed iron nitride nanoparticles effectively catalyze the conversion of LiPSs to Li2S, owing to their high electronic conductivity and strong binding power to LiPSs. Benefiting from this well-crafted composite nanostructure, the constructed FexN@C/S cathode demonstrated a fairly high discharge capacity of 1085 mAh g(-1) at 0.5 C initially, and a remaining value of 930 mAh g(-1 )after 200 cycles. In addition, it exhibits an excellent rate capability with a high initial discharge capacity of 889.8 mAh g(-1) at 2 C. This facile PIL-to-nanocarbon synthetic approach is applicable for the exquisite design of complex hybrid carbon nanostructures with potential use in electrochemical energy storage and conversion.}, language = {en} } @article{AbbasiXuKhezrietal.2022, author = {Abbasi, Ali and Xu, Yaolin and Khezri, Ramin and Etesami, Mohammad and Lin, C. and Kheawhom, Soorathep and Lu, Yan}, title = {Advances in characteristics improvement of polymeric membranes/separators for zinc-air batteries}, series = {Materials Today Sustainability}, volume = {18}, journal = {Materials Today Sustainability}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2589-2347}, doi = {10.1016/j.mtsust.2022.100126}, pages = {17}, year = {2022}, abstract = {Zinc-air batteries (ZABs) are gaining popularity for a wide range of applications due to their high energy density, excellent safety, and environmental friendliness. A membrane/separator is a critical component of ZABs, with substantial implications for battery performance and stability, particularly in the case of a battery in solid state format, which has captured increased attention in recent years. In this review, recent advances as well as insight into the architecture of polymeric membrane/separators for ZABs including porous polymer separators (PPSs), gel polymer electrolytes (GPEs), solid polymer electrolytes (SPEs) and anion exchange membranes (AEMs) are discussed. The paper puts forward strategies to enhance stability, ionic conductivity, ionic selectivity, electrolyte storage capacity and mechanical properties for each type of polymeric membrane. In addition, the remaining major obstacles as well as the most potential avenues for future research are examined in detail.}, language = {en} } @article{XieMeiXuetal.2021, author = {Xie, Dongjiu and Mei, Shilin and Xu, Yaolin and Quan, Ting and Haerk, Eneli and Kochovski, Zdravko and Lu, Yan}, title = {Efficient sulfur host based on yolk-shell iron oxide/sulfide-carbon nanospindles for lithium-sulfur batteries}, series = {ChemSusChem : chemistry, sustainability, energy, materials}, volume = {14}, journal = {ChemSusChem : chemistry, sustainability, energy, materials}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1864-5631}, doi = {10.1002/cssc.202002731}, pages = {1404 -- 1413}, year = {2021}, abstract = {Numerous nanostructured materials have been reported as efficient sulfur hosts to suppress the problematic "shuttling" of lithium polysulfides (LiPSs) in lithium-sulfur (Li-S) batteries. However, direct comparison of these materials in their efficiency of suppressing LiPSs shuttling is challenging, owing to the structural and morphological differences between individual materials. This study introduces a simple route to synthesize a series of sulfur host materials with the same yolk-shell nanospindle morphology but tunable compositions (Fe3O4, FeS, or FeS2), which allows for a systematic investigation into the specific effect of chemical composition on the electrochemical performances of Li-S batteries. Among them, the S/FeS2-C electrode exhibits the best performance and delivers an initial capacity of 877.6 mAh g(-1) at 0.5 C with a retention ratio of 86.7 \% after 350 cycles. This approach can also be extended to the optimization of materials for other functionalities and applications.}, language = {en} } @article{MeiXuPriestleyetal.2020, author = {Mei, Shilin and Xu, Xiaohui and Priestley, Rodney D. and Lu, Yan}, title = {Polydopamine-based nanoreactors: synthesis and applications in bioscience and energy materials}, series = {Chemical science}, volume = {11}, journal = {Chemical science}, number = {45}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2041-6520}, doi = {10.1039/d0sc04486e}, pages = {12269 -- 12281}, year = {2020}, abstract = {Polydopamine (PDA)-based nanoreactors have shown exceptional promise as multifunctional materials due to their nanoscale dimensions and sub-microliter volumes for reactions of different systems. Biocompatibility, abundance of active sites, and excellent photothermal conversion have facilitated their extensive use in bioscience and energy storage/conversion. This minireview summarizes recent advances in PDA-based nanoreactors, as applied to the abovementioned fields. We first highlight the design and synthesis of functional PDA-based nanoreactors with structural and compositional diversity. Special emphasis in bioscience has been given to drug/protein delivery, photothermal therapy, and antibacterial properties, while for energy-related applications, the focus is on electrochemical energy storage, catalysis, and solar energy harvesting. In addition, perspectives on pressing challenges and future research opportunities regarding PDA-based nanoreactors are discussed.}, language = {en} }