Review—Innovative Polymeric Materials for Better RechargeableBatteries: Strategies from CIC Energigune

The need for sustainable energy sources and their efficient utilization has motivated extensive explorations of new electrolytes, electrodes, and alternative battery chemistries departing from current lithium-ion battery ( LIB) technologies. The evolution and development of rechargeable batteries are tightly linked to the research of polymeric materials, such as polymer electrolytes and redox-active polymeric electrodes, separators, and binders, etc. In this contribution, we review the recent progresses on polymer electrolytes and redox-active polymeric electrodes developed in CIC Energigune with particular attention paid to the molecular designing and engineering. On the basis of our knowledge and experience accumulated in rechargeable batteries, further developments and improvements on the properties of these polymeric materials for building better rechargeable batteries are discussed. (c) The Author(s) 2019. Published by ECS.This work was supported by GV-ELKARTEK-2016 from the Basque Government, and MINECO RETOS (Ref: ENE2015-64907-C2-1-R) from Spanish Government. H.Z. thanks the Basque Government for the Berrikertu program (1-AFW-2017-2). This manuscript is dedicated to the 73th birthday of Prof. Dr. Michel Armand, who ushered theoretical concepts leading to practical applications in energy-related electrochemistry

Structure, Composition, Transport Properties, and Electrochemical Performance of the Electrode-Electrolyte Interphase in Non-Aqueous Na-Ion Batteries

[EN] Rechargeable Li-ion battery technology has progressed due to the development of a suitable combination of electroactive materials, binders, electrolytes, additives, and electrochemical cycling protocols that resulted in the formation of a stable electrode-electrolyte interphase. It is expected that Na-ion technology will attain a position comparable to Li-ion batteries dependent on advancements in establishing a stable electrode-electrolyte interphase. However, Li and Na are both alkali metals with similar characteristics, yet the physicochemical properties of these systems differ. For this reason, a detailed study on the electrode-electrolyte interphase properties, composition, and structure is required to understand the factors that influence the battery's behavior. Herein, the research that has been performed on the electrode-electrolyte interphase for both anode and cathode in the most important families of electrode materials, including carbonate ester-based and advanced electrolytes such as ether-based carbonates and ionic liquids is presented.Ministerio de Ciencia, Innovación y Universidades. Grant Number: PID2019- 107468RB-C21 Gobierno Vasco Eusko Jaurlaritza. Grant Number: IT1226-1

Influence of the Current Density on the Interfacial Reactivity of Layered Oxide Cathodes for Sodium-Ion Batteries

The full commercialization of sodium-ion batteries (SIBs) is still hindered by their lower electrochemical performance and higher cost ($ W-1 h(-1)) with respect to lithium-ion batteries. Understanding the electrode-electrolyte interphase formation in both electrodes (anode and cathode) is crucial to increase the cell performance and, ultimately, reduce the cost. Herein, a step forward regarding the study of the cathode-electrolyte interphase (CEI) by means of X-ray photoelectron spectroscopy (XPS) has been carried out by correlating the formation of the CEI on the P2-Na0.67Mn0.8Ti0.2O2 layered oxide cathode with the cycling rate. The results reveal that the applied current density affects the concentration of the formed interphase species, as well as the thickness of CEI, but not its chemistry, indicating that the electrode-electrolyte interfacial reactivity is mainly driven by thermodynamic factors.The authors would like to thank B. Acebedo for her support with materials synthesis, characterization, and testing, and E. Gonzalo for the fruitful discussions. M.Z. thanks the Basque Government for her Post-doc fellowship (POS_2017_1_0006). HIU authors (M.Z and S.P.) acknowledge the Helmholtz Association Basic funding. Open Access Funding provided by Universita degli Studi di Camerino within the CRUI-CARE Agreement

Graphene as Vehicle for Ultrafast Lithium Ion Capacitor Development Based on Recycled Olive Pit Derived Carbons

Herein we report a series of lithium ion capacitors (LICs) with extraordinary energy-to-power ratios based on olive pit recycled carbons and supported on graphene as a conducting matrix. LICs typically present limited energy densities at high power densities due to the sluggish kinetics of the battery-type electrode. To circumvent this limitation, the hard carbon (HC) was embedded in a reduced graphene oxide (rGO) matrix. The addition of rGO into the negative electrode not only forms a 3D interpenetrating carbon network but also wraps HC particles, facilitating ion diffusion and enhancing the electronic conductivity notably at high power densities. Electrochemical impedance spectroscopy (EIS) analysis reveals that charge-transfer resistance at electrode-electrolyte interphase and the charge-transport resistance within the electrode are considerably lower in the presence of rGO. In addition, charge-transport resistance remains constant upon cycling even at increasing current densities. Capacity gain at high current densities, owing to the reduction of the electrode resistance, triggers the overall LIC performance, allowing for the assembly of an ultrafast LIC delivering up to 200 Wh kg(AM)(-1) at low power rates and 100 Wh kg(AM)(-1). (C) The Author(s) 2019. Published by ECS.We thank the European Union (Graphene Flagship, Core 2, grant number 785219), the Spanish Ministry of Science and Innovation (MICINN/FEDER) (RTI2018-096199-B-I00) and the Basque Government (Elkartek 2018) for the financial support of this work. M. Arnaiz thanks the Spanish Ministry of Science, Innovation and Universities for her FPU pre-doctoral fellowship (FPU15/04876)

Role of the voltage window on the capacity retention of P2-Na2/3[Fe1/2Mn1/2]O2 cathode material for rechargeable sodium-ion batteries

[EN] P2-Na-2/3[Fe1/2Mn1/2]O-2 layered oxide is a promising high energy density cathode material for sodium-ion batteries. However, one of its drawbacks is the poor long-term stability in the operating voltage window of 1.5-4.25 V vs Na+/Na that prevents its commercialization. In this work, additional light is shed on the origin of capacity fading, which has been analyzed using a combination of experimental techniques and theoretical methods. Electrochemical impedance spectroscopy has been performed on P2-Na-2/3[Fe1/2Mn1/2]O-2 half-cells operating in two different working voltage windows, one allowing and one preventing the high voltage phase transition occurring in P2-Na-2/3[Fe1/2Mn1/2]O-2 above 4.0 V vs Na+/Na; so as to unveil the transport properties at different states of charge and correlate them with the existing phases in P2-Na-2/3[Fe1/2Mn1/2]O-2. Supporting X-ray photoelectron spectroscopy experiments to elucidate the surface properties along with theoretical calculations have concluded that the formed electrode-electrolyte interphase is very thin and stable, mainly composed by inorganic species, and reveal that the structural phase transition at high voltage from P2- to "Z"/OP4-oxygen stacking is associated with a drastic increased in the bulk electronic resistance of P2-Na-2/3[Fe1/2Mn1/2]O-2 electrodes which is one of the causes of the observed capacity fading. P2-Na-2/3[Fe1/2Mn1/2]O-2 is a promising high energy density cathode material for rechargeable sodium-ion batteries, but its poor long-term stability in the operating voltage window of 1.5-4.25 V vs Na+/Na hinders its commercial application. Here, the authors use a combination of electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and DFT calculations to investigate the origin of the capacity fading, which is attributed to an increase in bulk electronic resistance at high voltage that, among other factors, is nested in a structural phase transition.M.Z. thanks the Government of the Basque Country for Ph.D. funding through a Predoctoral fellowship and her stage at the University of Camerino by "EGONLABUR" Fellowship. B. Acebedo and M. Jauregui are acknowledged for their technical support with material synthesis and powder XRD measurements. O.L. thanks J.X Lian for his insight into generating the DOS graphs. Financial support from the Basque Government (Elkartek20 CIC energiGUNE) and from the Ministerio de Economia y Competitividad of the Spanish Government (ENE2013-44330-R) is also acknowledged

On the Road to Sustainable Energy Storage Technologies: Synthesis of Anodes for Na-Ion Batteries from Biowaste

Hard carbon is one of the most promising anode materials for sodium-ion batteries. In this work, new types of biomass-derived hard carbons were obtained through pyrolysis of different kinds of agro-industrial biowaste (corncob, apple pomace, olive mill solid waste, defatted grape seed and dried grape skin). Furthermore, the influence of pretreating the biowaste samples by hydrothermal carbonization and acid hydrolysis was also studied. Except for the olive mill solid waste, discharge capacities typical of biowaste-derived hard carbons were obtained in every case (≈300 mAh·g−1 at C/15). Furthermore, it seems that hydrothermal carbonization could improve the discharge capacity of biowaste samples derived from different nature at high cycling rates, which are the closest conditions to real applications.This research was funded by the Ministerio de Ciencia e Innovación (PID2019-107468RB-C21) and Gobierno Vasco/Eusko Jaurlaritza (IT-1226-19 and IT-993-16)

Influence of the Ambient Storage of LiNi0.8Mn0.1Co0.1O2 Powder and Electrodes on the Electrochemical Performance in Li-ion Technology

Nickel-rich LiNi0.8Mn0.1Co0.1O2 (NMC811) is one of the most promising Li-ion battery cathode materials and has attracted the interest of the automotive industry. Nevertheless, storage conditions can affect its properties and performance. In this work, both NMC811 powder and electrodes were storage-aged for one year under room conditions. The aged powder was used to prepare electrodes, and the performance of these two aged samples was compared with reference fresh NMC811 electrodes in full Li-ion coin cells using graphite as a negative electrode. The cells were subjected to electrochemical as well as ante- and postmortem characterization. The performance of the electrodes from aged NM811 was beyond expectations: the cycling performance was high, and the power capability was the highest among the samples analyzed. Materials characterization revealed modifications in the crystal structure and the surface layer of the NMC811 during the storage and electrode processing steps. Differences between aged and fresh electrodes were explained by the formation of a resistive layer at the surface of the former. However, the ageing of NMC811 powder was significantly mitigated during the electrode processing step. These novel results are of interest to cell manufacturers for the widespread implementation of NMC811 as a state-of-the-art cathode material in Li-ion batteries.This work was supported by European Union’s Horizon 2020 research and innovation programme [No. 814389 (SPIDER project)]; and the CDTI—Ministerio De Ciencia e Innovación’s ‘CERVERA Centros Tecnológicos’ program [CER-20191006 (ALMAGRID project)]. V.P. and T.R. also wish to thank the funding from Gobierno Vasco/Eusko Jaurlaritza (IT-1226-19)

Towards a High-Power Si@graphite Anode for Lithium Ion Batteries through a Wet Ball Milling Process

Silicon-based anodes are extensively studied as an alternative to graphite for lithium ion batteries. However, silicon particles suffer larges changes in their volume (about 280%) during cycling, which lead to particles cracking and breakage of the solid electrolyte interphase. This process induces continuous irreversible electrolyte decomposition that strongly reduces the battery life. In this research work, different silicon@graphite anodes have been prepared through a facile and scalable ball milling synthesis and have been tested in lithium batteries. The morphology and structure of the different samples have been studied using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and scanning and transmission electron microscopy. We show how the incorporation of an organic solvent in the synthesis procedure prevents particles agglomeration and leads to a suitable distribution of particles and intimate contact between them. Moreover, the importance of the microstructure of the obtained silicon@graphite electrodes is pointed out. The silicon@graphite anode resulted from the wet ball milling route, which presents capacity values of 850 mA h/g and excellent capacity retention at high current density (≈800 mA h/g at 5 A/g).This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 785219-GrapheneCore2

Flat-shaped carbon-graphene microcomposites as electrodes for high energy supercapacitors

Herein, we report a simple approach for the preparation of phosphate-functionalized carbonaceous graphene-based composites. The homogeneous deposition of a thin layer of phenolic resin on the surface of graphene oxide (GO) sheets was achieved using phosphoric acid as the polymerization catalyst and functionalization agent. Subsequent pyrolysis of the composite yielded homogeneous lamellar-shaped microstructured porous carbon-graphene composites combining enhanced molecular diffusion and high electron transfer. In order to elucidate the effect of GO and porosity on the supercapacitor performance, a graphene free sample and a KOH-activated composite were also prepared and tested in a two-electrode configuration using aqueous and organic electrolytes. It was found that the presence of GO and the KOH activation lead to an increase in the specific surface area combined with a progressive widening of the pores. As a result, the KOH-activated composite reached specific capacitances of 211 and 105 F g(-1) when using 1 M H2SO4 and 1.5 M Et4NBF4 electrolytes, respectively. It was also found that phosphorus-functionalization of electrodes leads to an operating voltage of 1.3 V in the aqueous electrolyte, resulting in a considerable increase of the energy density of the cell. Finally, both non-activated and activated graphene-based composites provide excellent capacitance retention, energy and power densities and cycling stability.We thank the European Union (Graphene Flagship, Core 2, Grant number 785219), the Spanish Ministry of Science and Innovation (MICINN/FEDER) (MAT2015-64617-C2-2-R and RTI2018-096199-B-I00) and the Basque Government (Elkartek 2018) for the financial support of this work. J. L. G. U. is very thankful to the "Ministerio de ciencia, innovacion y universidades" for the FPU grant (16/03498). We also want to acknowledge the company GRAPHENEA for supplying the graphene oxide used in this work and Dr M. A. Munoz for the acquisition of the XPS spectrum

M(C6H16N3)2(VO3)4 as heterogeneous catalysts. Study of three new hybrid vanadates of cobalt(II), nickel(II) and copper(II) with 1-(2-aminoethyl)piperazonium.

postprintThree new hybrid vanadates have been synthesized under hydrothermal conditions with the formula M(C6H16N3)2(VO3)4, where M= Co(II), Ni(II) and Cu(II). The structural analyses show that the phases are isostructural and crystallize in the monoclinic space group P21/c. These compounds show a two-dimensional crystal structure, with sheets composed of [VO3] chains and metal centres octahedrically coordinated, chelated by two 1(2-aminoethyl)pyperazonium ligands. The thermal study reveals that copper containing phase is less stable than cobalt and nickel containing ones. The IR spectra of the three phases are very similar, with little differences in the inorganic bond region of the copper containing phase. The UV-visible spectra show that the cobalt(II) and the nickel(II) are in slightly distorted octahedral environments. The catalytic tests show that the phases act as heterogeneous catalysts for the selective oxidization of alkyl aryl sulfides, with both H2O2 and tert-butylhydroperoxide as oxidizing agents. The influence of the steric hindrance in the kinetic profile had been studied. The catalytic reactions induce the partial amorphization of the phases.Ministerio de Ciencia e Innovación: MAT2010-15375, MAT2006-14274-C02- 02. Gobierno Vasco: IT177-0