Transposition of a weighted ah-throughput model to another li-ion technology: is the model still valid? new insights on the mechanisms

The increasing interest in electric vehicles powered by rechargeable batteries, combined with the wide development of powerful lithium-ion batteries as a renewable energy storage system have raised the need for battery ageing characterization. Several models have been developed for this purpose, including empirical, fatigue and mathematical ones. One of the main issue of these approaches consists of the universality, when extension is required to other chemistries or solicitations. Electrochemical models are supposedly the most extensible. The Weighted Ah-Throughput Model takes into account that certain operating conditions may lead either to an increase or a decrease of the rate of ageing. It modulates the impact of the exchanged Ah by the temperature, the C-rate and the state of charge (SOC), both in calendar and active regime. This influence of the parameters is described here, and compared between two Li-ion chemistries: LFP and NCA. The similitudes enable us to extract the generic hidden mechanisms that, by nature, the fatigue modelling methods do not provide. This innovative method enables us to reach energetic behavior laws. We finally suggest improvements on the tests matrix used to define the model, to better fit the outcome of the study

Effect of boron addition on the electrochemical properties of LiFePO4

III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce

Memristive and neuromorphic behavior in a Li x CoO 2 nanobattery

International audienceThe phenomenon of resistive switching (RS), which was initially linked to non-volatile resistive memory applications, has recently also been associated with the concept of memristors, whose adjustable multilevel resistance characteristics open up unforeseen perspectives in cognitive computing. Herein, we demonstrate that the resistance states of Li(x)CoO2 thin film-based metal-insulator-metal (MIM) solid-state cells can be tuned by sequential programming voltage pulses, and that these resistance states are dramatically dependent on the pulses input rate, hence emulating biological synapse plasticity. In addition, we identify the underlying electrochemical processes of RS in our MIM cells, which also reveal a nanobattery-like behavior, leading to the generation of electrical signals that bring an unprecedented new dimension to the connection between memristors and neuromorphic systems. Therefore, these LixCoO2-based MIM devices allow for a combination of possibilities, offering new perspectives of usage in nanoelectronics and bio-inspired neuromorphic circuits

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Transposition of a weighted ah-throughput model to another li-ion technology: is the model still valid? new insights on the mechanisms

The increasing interest in electric vehicles powered by rechargeable batteries, combined with the wide development of powerful lithium-ion batteries as a renewable energy storage system have raised the need for battery ageing characterization. Several models have been developed for this purpose, including empirical, fatigue and mathematical ones. One of the main issue of these approaches consists of the universality, when extension is required to other chemistries or solicitations. Electrochemical models are supposedly the most extensible. The Weighted Ah-Throughput Model takes into account that certain operating conditions may lead either to an increase or a decrease of the rate of ageing. It modulates the impact of the exchanged Ah by the temperature, the C-rate and the state of charge (SOC), both in calendar and active regime. This influence of the parameters is described here, and compared between two Li-ion chemistries: LFP and NCA. The similitudes enable us to extract the generic hidden mechanisms that, by nature, the fatigue modelling methods do not provide. This innovative method enables us to reach energetic behavior laws. We finally suggest improvements on the tests matrix used to define the model, to better fit the outcome of the study

Electrode/electrolyte interface reactivity in high-voltage spinel LiMn 1.6Ni0.4O4/Li4Ti5O 12 lithium-ion battery

cited By 129International audienceHigh-voltage spinel oxides combined with Li4Ti5O 12 result in 3 V lithium-ion batteries with a high power capability; however, the electrochemical performances are limited by electrode/electrolyte interfacial reactivity at high potential. We have investigated electrode/electrolyte interfaces in LiMn1.6Ni0.4O 4/Li4Ti5O12 cells by X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectrocopy (EIS). EIS has shown that both electroadsorption and film-formation mechanisms occur at the positive electrode. XPS has revealed that very low amounts of lithiated species are deposited at the surface of the positive electrode, despite the high potential, but that great amounts of organic species are deposited. Interesting results were obtained for the Li4Ti 5O12 electrode. Whereas Li4Ti5O 12 is usually considered as a passivation-free electrode material, large amounts of organic and inorganic species were deposited at the surface of this electrode. The question of a possible interaction between both electrodes in the formation mechanisms of surface films is discussed. © 2010 American Chemical Society