High frequency response of adenine-derived carbon in aqueous electrochemical capacitor

Electrochemical capacitors are attractive power sources, especially when they are able to operate at high frequency (high current regime). In order to meet this requirement their constituents should be made of high conductivity materials with a suitable porosity. In this study, enhanced power and simultaneously high capacitance (120 F g−1 at 1 Hz or 10 A g−1) electrode material obtained from carbonized adenine precursor is presented. A micro/mesoporous character of the carbon with optimal pore size ratio and high surface area was proven by the physicochemical characterization. The beneficial pore structure and morphology resembling highly conductive carbon black, together with a significant nitrogen content (5.5%) allow for high frequency response of aqueous capacitor to be obtained. The carbon/carbon symmetric capacitor (in 1 mol L−1 Li2SO4) has been tested to the voltage of 1.5 V. The cyclic voltammetry indicates a good electrochemical response even at high scan rate (50 mV s−1). The cyclability of the capacitor is comparable to the one operating with commercial carbon (YP50F). The adenine-based capacitor is especially favourable for stationary applications requiring high power.Partners acknowledge M-ERA.NET network, MCIN/AEI/10.13039/501100011033 (Ref. PCI2019–103637), CIBER-BBN, ICTS ‘‘NANBIOSIS’’, ICTS ELECMI node "Laboratorio de Microscopias Avanzadas", National Science Centre, Poland (2018/30/Z/ST4/00901), and Ministrstvo za izobraževanje, znanost in šport for financial support and the grant of Ministry of Science and Higher Education in Poland, no. 0911/SBAD/2101. A.V., B.T., E.T. and R.D. additionally acknowledge financial support from the Slovenian Research Agency (ARRS) research core funding P2–0393.Peer reviewe

New non-graphitizable carbon/nanocrystals hybrids with enhanced electrochemical properties for Na-ion batteries

Resumen del trabajo presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.Peer reviewe

Simple surface treatment improves performance of carbon materials for sodium ion battery anodes

Hard carbons are the most extended anode materials for sodium-ion batteries (SIBs); however, they suffer from several limitations such as low stability, poor rate performance and low initial Coulombic efficiency (iCE). Herein, a simple, fast, and low-cost surface treatment at room temperature using short-chain organic molecules: 3-mercaptopropionic acid (MPA), 1,2-ethanedithiol (EDT) and oxalic acid (OxA) has been applied to a hard carbon (C1400).The carbons treated with sulfur containing molecules (MPA or EDT) exhibit higher capacity (12 % capacity enhancement after 100th cycles at C/10 and 18 % enhancement at 1C vs. C1400). The introduction of these ligands leads to improved micropore blockage, helping in the reversible insertion of Na ions. Moreover, ex-situ X-ray photoelectron spectroscopy (XPS) analyses demonstrate that thiol functional groups promote the formation of favorable NaF and Na2O-rich solid electrolyte interfaces (SEI) leading to and faster sodium diffusion in the plateau region. Additionally, MPA and EDT treatments have been applied to a soft carbon (Vulcan XC-72R) resulting in a substantial 30 % capacity improvement after 100 cycles at 1C.These results demonstrate the wide applicability of the method as a straightforward and efficient strategy for improving the electrochemical properties of carbon anodes used in SIBs.Authors acknowledge ERA.NET network for funding NOEL project, SA, MPL and MB acknowledge MCIN/AEI/10.13039/501100011033 (Ref: PRTR-C17.I1 with funding from European Union NextGenerationEU, promoted by the Government of Aragon, and PCI2019–10363), CIBER-BBN, ICTS ‘‘NANBIOSIS’’, instrumentation and technical advice provided by the National Facility ICTS ELECMI node “Laboratorio de Microscopias Avanzadas”, and Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza. BT, AV and RD further acknowledge financial support from the Slovenian Research and Innovation Agency (ARIS), research core funding P2-0423 and project N2-0266.Peer reviewe