Comparative study of the implementation of tin and titanium oxide nanoparticles as electrodes materials in Li-ion batteries

Transition metal oxides potentially present higher specific capacities than the current anodes based on carbon, providing an increasing energy density as compared to commercial Li-ion batteries. However, many parameters could influence the performance of the batteries, which depend on the processing of the electrode materials leading to different surface properties, sizes or crystalline phases. In this work a comparative study of tin and titanium oxide nanoparticles synthesized by different methods, undoped or Li doped, used as single components or in mixed ratio, or alternatively forming a composite with graphene oxide have been tested demonstrating an enhancement in capacity with Li doping and better cyclability for mixed phases and composite anodes

Ellagic acid - a novel organic electrode material for high capacity lithium ion batteries

Ellagic acid, a naturally occurring polyphenol, extracted from pomegranate husk, is found to be a very good organic electrode material for rechargeable lithium batteries with high reversible capacities of similar to 450 and 200 mA h g(-1) at C/10 and C/2.5 discharge rates, respectively; ex situ NMR studies reveal possible lithiation-delithiation modes at different stages of the charge-discharge process

Cryogenic Laser Ablation Reveals Short-Circuit Mechanism in Lithium Metal Batteries

The dramatic 50% improvement in energy density that Li-metal anodes offer in comparison to graphite anodes in conventional lithium (Li)-ion batteries cannot be realized with current cell designs because of cell failure after a few cycles. Often, failure is caused by Li dendrites that grow through the separator, leading to short circuits. Here, we used a new characterization technique, cryogenic femtosecond laser cross sectioning and subsequent scanning electron microscopy, to observe the electroplated Li-metal morphology and the accompanying solid electrolyte interphase (SEI) into and through the intact coin cell battery's separator, gradually opening pathways for soft-short circuits that cause failure. We found that separator penetration by the SEI guided the growth of Li dendrites through the cell. A short-circuit mechanism via SEI growth at high current density within the separator is provided. These results will inform future efforts for separator and electrolyte design for Li-metal anodes

Cryogenic Laser Ablation Reveals Short-Circuit Mechanism in Lithium Metal Batteries

The dramatic 50% improvement in energy density that Li-metal anodes offer in comparison to graphite anodes in conventional lithium (Li)-ion batteries cannot be realized with current cell designs because of cell failure after a few cycles. Often, failure is caused by Li dendrites that grow through the separator, leading to short circuits. Here, we used a new characterization technique, cryogenic femtosecond laser cross sectioning and subsequent scanning electron microscopy, to observe the electroplated Li-metal morphology and the accompanying solid electrolyte interphase (SEI) into and through the intact coin cell battery's separator, gradually opening pathways for soft-short circuits that cause failure. We found that separator penetration by the SEI guided the growth of Li dendrites through the cell. A short-circuit mechanism via SEI growth at high current density within the separator is provided. These results will inform future efforts for separator and electrolyte design for Li-metal anodes

Computer simulations of the influence of geometry in the performance of conventional and unconventional lithium-ion batteries

In order to optimize battery performance, different geometries have been evaluated taking into account their suitability for different applications. These different geometries include conventional, interdigitated batteries and unconventional geometries such as horseshoe, spiral, ring, antenna and gear batteries. The geometry optimization was performed by the finite element method, applying the Doyle/Fuller/Newman model. At 330C, the capacity values for conventional, ring, spiral, horseshoe, gear and interdigitated geometries are 0,58 Ahm -2 , 149 Ahm -2 , 182 Ahm -2 , 216 Ahm -2 , 289 Ahm - 2 and 318 Ahm -2 , respectively. The delivered capacity depends on geometrical parameters such as maximum distance for the ions to move to the current collector, d_max, distance between of current collectors, d_cc, as well as the thickness of separator and electrodes, allowing to tailor battery performance and geometry for specific applications.This work is funded by FEDER funds through the “Programa Operacional Factores de Competitividade – COMPETE” and by national funds from FCT – Fundação para a Ciência e a Tecnologia, in the framework of the strategic project Strategic Project PEST-C/FIS/UI607/2014. C.M.C. also thanks the FCT for the grant SFRH/BPD/112547/2015