查看更多>>摘要：Rechargeable sodium-ion batteries usually suffer from accelerated electrode destruction at high temperatures and high synthesis costs of electrode materials.Therefore,it is highly desirable to explore novel organic electrodes considering their cost-effectiveness and large adaptability to volume changes.Herein,natural biomass,pristine lignin,is employed as the sodium-ion battery anodes,and their sodium storage performance is investigated at room temperature and 60 ℃.The lignin anodes exhibit excellent high-temperature sodium-ion battery performance.This mainly results from the generation of abundant reactive sites(C=O)due to the high temperature-induced homogeneous cleavage of the Cβ-O bond in the lignin macromolecule.This work can inspire researchers to explore other natural organic materials for large-scale applications and high-value utilization in advanced energy storage devices.
查看更多>>摘要：The development of freestanding and binder-free electrode is an effective approach to perform the inherent capacity of active materials and promote the mechanism study by minimizing the interference from additives.Herein,we construct a freestanding cathode composed of MoS3/PPy nanowires(NWs)deposited on porous nickel foam(NF)(MoS3/PPy/NF)through electrochemical methods,which can work efficiently as sulfur-equivalent cathode material for Li-S batteries.The structural stability of the MoS3/PPy/NF cathode is greatly enhanced due to its significant tolerance to the volume expansion of MoS3 during the lithiation process,which we ascribe to the flexible 3D framework of PPy NWs,leading to superior cycling performance compared to the bulk-MoS3/NF reference.Eliminating the interference of binder and carbon additives,the evolution of the chemical and electronic structure of Mo and S species during the discharge/charge was studied by X-ray absorption near-edge spectroscopy(XANES).The formation of lithium polysulfides was excluded as the driving cathode reaction mechanism,suggesting the great potential of MoS3 as a promising sulfur-equivalent cathode material to evade the shuttle effect for Li-S batteries.The present study successfully demonstrates the importance of structural design of freestanding electrode enhancing the cycling performances and revealing the corresponding mechanisms.
查看更多>>摘要：Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the sustainable development of energy and the environment.Herein,a facile collagen microstructure modulation strategy is proposed to construct a nitrogen/oxygen dual-doped hierarchically porous carbon fiber with ultrahigh specific surface area(2788 m2 g-1)and large pore volume(4.56 cm3 g-1)via local microfibrous breakage/disassembly of natural structured proteins.Combining operando spectroscopy and density functional theory unveil that the dual-heteroatom doping could effectively regulate the electronic structure of carbon atom framework with enhanced electric conductivity and electronegativity as well as decreased diffusion resistance in favor of rapid pseudocapacitive-dominated Li+-storage(353 mAh g-1 at 10 A g-1).Theoretical calculations reveal that the tailored micro-/mesoporous structures favor the rapid charge transfer and ion storage,synergistically realizing high capacity and superior rate performance for NPCF-H cathode(75.0 mAh g-1 at 30 A g-1).The assembled device with NPCF-H as both anode and cathode achieves extremely high energy density(200 Wh kg-1)with maximum power density(42 600 W kg-1)and ultralong lifespan(80％capacity retention over 10 000 cycles).
查看更多>>摘要：Biaxially oriented polypropylene(BOPP)is one of the most commonly used commercial capacitor films,but its upper operating temperature is below 105 ℃ due to the sharply increased electrical conduction loss at high temperature.In this study,growing an inorganic nanoscale coating layer onto the BOPP film's surface is proposed to suppress electrical conduction loss at high temperature,as well as increase its upper operating temperature.Four kinds of inorganic coating layers that have different energy band structure and dielectric property are grown onto the both surface of BOPP films,respectively.The effect of inorganic coating layer on the high-temperature energy storage performance has been systematically investigated.The favorable coating layer materials and appropriate thickness enable the BOPP films to have a significant improvement in high-temperature energy storage performance.Specifically,when the aluminum nitride(AIN)acts as a coating layer,the AIN-BOPP-AIN sandwich-structured films possess a discharged energy density of 1.5 J cm-3 with an efficiency of 90％at 125 ℃,accompanying an outstandingly cyclic property.Both the discharged energy density and operation temperature are significantly enhanced,indicating that this efficient and facile method provides an important reference to improve the high-temperature energy storage performance of polymer-based dielectric films.
查看更多>>摘要：The realization of a stable lithium-metal free(LiMF)sulfur battery based on amorphous carbon anode and lithium sulfide(Li2S)cathode is here reported.In particular,a biomass waste originating full-cell combining a carbonized brewer's spent grain(CBSG)biochar anode with a Li2S-graphene composite cathode(Li2S70Gr30)is proposed.This design is particularly attractive for applying a cost-effective,high performance,environment friendly,and safe anode material,as an alternative to standard graphite and metallic lithium in emerging battery technologies.The anodic and cathodic materials are characterized in terms of structure,morphology and composition through X-ray diffraction,scanning and transmission electron microscopy,X-ray photoelectron and Raman spectroscopies.Furthermore,an electrochemical characterization comprising galvanostatic cycling,rate capability and cyclic voltammetry tests were carried out both in half-cell and full-cell configurations.The systematic investigation reveals that unlike graphite,the biochar electrode displays good compatibility with the electrolyte typically employed in sulfur batteries.The CBSG/Li2S70Gr30 full-cell demonstrates an initial charge and discharge capacities of 726 and 537 mAh g-1,respectively,at 0.05C with a coulombic efficiency of 74％.Moreover,it discloses a reversible capacity of 330 mAh g-1(0.1 C)after over 300 cycles.Based on these achievements,the CBSG/Li2S70Gr30 battery system can be considered as a promising energy storage solution for electric vehicles(EVs),especially when taking into account its easy scalability to an industrial level.
查看更多>>摘要：As a critical role in battery systems,polymer binders have been shown to efficiently suppress the lithium polysulfide shuttling and accommodate volume changes in recent years.However,preparation processes and safety,as the key criterions for Li-S batteries'practical applications,still attract less attention.Herein,an aqueous multifunction binder(named PEI-TIC)is prepared via an easy and fast epoxy-amine ring-opening reaction(10 min),which can not only give the sulfur cathode a stable mechanical property,a strong chemical adsorption and catalytic conversion ability,but also a fire safety improvement.The Li-S batteries based on the PEI-TIC binder display a high discharge capacity(1297.8 mAh g-1),superior rate performance(823.0 mAh g-1 at 2 C),and an ultralow capacity decay rate of 0.035％over more than 800 cycles.Even under 7.1 mg cm-2 S-loaded,the PEI-TIC electrode can also achieve a high areal capacity of 7.2 mA h g-1 and excellent cycling stability,confirming its application potential.Moreover,it is also noted that TG-FTIR test is performed for the first time to explore the flame-retardant mechanism of polymer binders.This work provides an economically and environmentally friendly binder for the practical application and inspires the exploration of the flame-retardant mechanism of all electrode components.
查看更多>>摘要：LiNixCoyAlzO2(NCA)cathode materials are drawing widespread attention,but the huge gap between the ideal and present cyclic stability still hinders their further commercial application,especially for the Ni-rich LiNixCoyAlzO2(x＞0.8,x+y+z=1)cathode material,which is owing to the structural degradation and particles'intrinsic fracture.To tackle the problems,Li0.5La2Al0.5O4 in situ coated and Mn compensating doped multilayer LiNi0.82Co0.14Al0.04O2 was prepared.XRD refinement indicates that La-Mn co-modifying could realize appropriate Li/Ni disorder degree.Calculated results and in situ XRD patterns reveal that the LLAO coating layer could effectively restrain crack in secondary particles benefited from the suppressed internal strain.AFM further improves as NCA-LM2 has superior mechanical property.The SEM,TEM,XPS tests indicate that the cycled cathode with LLAO-Mn modification displays a more complete morphology and less side reaction with electrolyte.DEMS was used to further investigate cathode-electrolyte interface which was reflected by gas evolution.NCA-LM2 releases less CO2 than NCA-P indexing on a more stable surface.The modified material presents outstanding capacity retention of 96.2％after 100 cycles in the voltage range of 3.0-4.4 V at 1C,13％higher than that of the pristine and 80.8％at 1 C after 300 cycles.This excellent electrochemical performance could be attributed to the fact that the high chemically stable coating layer of Li0.5La2Al0.5O4(LLAO)could enhance the interface and the Mn doping layer could suppress the influence of the lattice mismatch and distortion.We believe that it can be a useful strategy for the modification of Ni-rich cathode material and other advanced functional material.
查看更多>>摘要：Poly(ethylene oxide)(PEO)-based polymer electrolytes show the prospect in all-solid-state lithium metal batteries;however,they present limitations of low room-temperature ionic conductivity,and interfacial incompatibility with high voltage cathodes.Therefore,a salt engineering of 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide lithium salt(LiHFDF)/LiTFSI system was developed in PEO-based electrolyte,demonstrating to effectively regulate Li ion transport and improve the interfacial stability under high voltage.We show,by manipulating the interaction between PEO matrix and TFSI--HFDF-,the optimized solid-state polymer electrolyte achieves maximum Li+conduction of 1.24 × 10-4 S cm-1 at 40 ℃,which is almost 3 times of the baseline.Also,the optimized polymer electrolyte demonstrates outstanding stable cycling in the LiFePO4/Li and LiNi0.8Mn0.1Co0.1O2/Li(3.0-4.4 V,200 cycles)based all-solid-state lithium batteries at 40 ℃.
查看更多>>摘要：Crystalline γ-Ga2O3@rGO core-shell nanostructures are synthesized in gram scale,which are accomplished by a facile sonochemical strategy under ambient condition.They are composed of uniform γ-Ga2O3 nanospheres encapsulated by reduced graphene oxide(rGO)nanolayers,and their formation is mainly attributed to the existed opposite zeta potential between the Ga2O3 and rGO.The as-constructed lithium-ion batteries(LIBs)based on as-fabricated γ-Ga2O3@rGO nanostructures deliver an initial discharge capacity of 1000 mAh g-1 at 100 mA g-1 and reversible capacity of 600 mAh g-1 under 500 mA g-1 after 1000 cycles,respectively,which are remarkably higher than those of pristine γ-Ga2O3 with a much reduced lifetime of 100 cycles and much lower capacity.Ex situ XRD and XPS analyses demonstrate that the reversible LIBs storage is dominant by a conversion reaction and alloying mechanism,where the discharged product of liquid metal Ga exhibits self-healing ability,thus preventing the destroy of electrodes.Additionally,the rGO shell could act robustly as conductive network of the electrode for significantly improved conductivity,endowing the efficient Li storage behaviors.This work might provide some insight on mass production of advanced electrode materials under mild condition for energy storage and conversion applications.
Hak Hyeon LeeDong Su KimSwagotom SarkerJi Hoon Choi...
83-92页
查看更多>>摘要：Rh has been widely studied as a catalyst for the promising hydrazine oxidation reaction that can replace oxygen evolution reactions for boosting hydrogen production from hydrazine-containing wastewater.Despite Rh being expensive,only a few studies have examined its electrocatalytic mass activity.Herein,surface-limited cation exchange and electrochemical activation processes are designed to remarkably enhance the mass activity of Rh.Rh atoms were readily replaced at the Ni sites on the surface of NiOOH electrodes by cation exchange,and the resulting RhOOH compounds were activated by the electrochemical reduction process.The cation exchange-derived Rh catalysts exhibited particle sizes not exceeding 2 nm without agglomeration,indicating a decrease in the number of inactive inner Rh atoms.Consequently,an improved mass activity of 30 A mgRh-1 was achieved at 0.4 V versus reversible hydrogen electrode.Furthermore,the two-electrode system employing the same CE-derived Rh electrodes achieved overall hydrazine splitting over 36 h at a stable low voltage.The proposed surface-limited CE process is an effective method for reducing inactive atoms of expensive noble metal catalysts.
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