Advanced anode materials for sodium ion batteries: H2Ti3O7and TMNCN (TM=Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+) carbodiimides

207 p.La futura escasez de los combustibles fósiles (principal fuente de energía) y la contaminación generada por su utilización genera una necesidad de cambio del sistema energético actual. Por tanto, es necesario el aprovechamiento de las fuentes de energía renovables mediante el almacenamiento de energía en baterías. A pesar de las buenas prestaciones de las baterías de ion litio, la necesidad de buscar una tecnología más limpia y barata de alta densidad energética como son las baterías de ion sodio. Sin embargo, la imposibilidad de usar grafito como ánodo en estas baterías es la mayor desventaja. Por tanto, el proyecto de investigación se centra en el estudio de la caracterización estructural y electroquímica en dos diferentes familias de materiales para ser utilizados como electrodos negativos (ánodos) para baterías de ion sodio. En este trabajo se han estudiado las prestaciones electroquímicas de titanatos y carbodiimidas de metales de transición, así como experimentos de celdas completas para una buena caracterización del material. Para ello se han utilizado una gran variedad de técnicas experimentales de caracterización tanto estructural como electroquímica, que nos permite conocer los diferentes mecanismos de reacción de los materiales que presentan estos materiales dentro de la batería

From Lab to Manufacturing Line: Guidelines for the Development and Upscaling of Aqueous Processed NMC622 Electrodes

Lithium-ion batteries (LIBs) have facilitated the transition to a more sustainable energy model. Paradoxically, current high energy cathodes are industrially processed using organic solvents, which are deleterious for the environment. In this work, LiNi0.6Mn0.2Co0.2O2 (NMC622) high-energy cathode electrode was prepared at laboratory scale following a more environmentally friendly aqueous route. Several steps in the preparation of the electrodes (such as the drying temperature, drying air flux or pH buffering) were thoroughly optimized to enhance the quality of the water-processed electrodes. Afterwards, the recipe developed at laboratory scale was upscaled to a semi-industrial electrode coating line, to analyze the viability of the developed processing conditions into a realistic electrode manufacturing environment. The electrodes obtained were tested in full coin cells using graphite-based anodes as counter electrodes. Interestingly, the cycling performance of the cells based on water-processed electrodes was higher than that of organic-processed ones. It is evidenced that it is possible to manufacture electrodes for high energy density LIBs following environmentally friendly, cheaper, and industrially implementable electrode processing methods with no-penalty in the electrochemical performance.This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreements No 769929 (IMAGE) and No 814464 (Si-DRIVE)

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)

The Electrochemical Society The Electrochemical Society The following article is OPEN ACCESS In Situ Analysis of NMCmidgraphite Li-Ion Batteries by Means of Complementary Electrochemical Methods

Lithium-ion technology is considered as outstanding candidate for implementation in high energy density applications. Adjusting the cycling conditions of electrodes and monitoring the undergoing reactions are necessary to maximize their potentiality and ensure high performance and safe operation for end-users. Herein, in situ electrochemical impedance spectroscopy (EIS), direct current (DC) resistance and differential voltage analysis (DVA) are complementarily used to understand and predict the lifetime of LiNi0.6Mn0.2Co0.2O2 (NMC622) vs graphite coin cells cycled at different upper cut-off voltage (UCV). Lithium de/intercalation reactions in graphite, phase transitions in NMC and the formation of electrode-electrolyte interphases have been identified by DVA. Combined with EIS and DC resistance, the occurrence of these reactions has been monitored upon cycling. The main findings indicate that despite observing other detrimental phenomena (charge transfer resistance increase or irreversibility of NMC622 phase transitions), the different solid electrolyte interphase (SEI) formation and resistance with UCV are most relevant factors affecting cycle life. The loss of lithium inventory is the main cause of the capacity fade. The need of a stable SEI to delay the continuous electrolyte consumption is highlighted. The combined information provided by these techniques can be leveraged by battery management systems to optimize cell performance while cycling