An Aluminum/Graphite Battery with Ultra-High Rate Capability

A high-performance Al/graphite battery has been investigated, employing a natural graphite cathode (NG) and 1-ethyl-3-methylimidazolium chloride (EMIMCl):AlCl3 as electrolyte. The employed graphite is characterized by excellent reversibility as revealed by electrochemical tests and ex-situ XRD. The Al/EMIMCl:AlCl3/NG battery showed extraordinary performance in terms of rate capability, and cycle life. The cell delivered a capacity of 110 mAh g−1 at lower current values, retaining 90 % and 60 % of the capacity employing a current of 20 A g−1 and 50 A g−1, respectively (i. e., a complete charge-discharge cycle in 35 and 9 seconds, respectively). Furthermore, the cycling test performed using a current of 20 A g−1 revealed an extremely long calendar life of half million of cycles. The practical applicability of the investigated Al/graphite system has been ascertained; this involved estimating the energy efficiency as a function of current rate and carefully calculating the practical energy densities that can be obtained from the system

(119)Sn Mössbauer spectroscopy study of the mechanism of lithium reaction with self-organized Ti1/2Sn1/2O2 nanotubes.

International audience: Novel self-organized Ti1/2Sn1/2O2 nanotubes can be produced by the electrochemical anodization of co-sputtered Ti-Sn thin-films. Combined X-ray photoelectron spectroscopy and (119)Sn Mössbauer spectroscopy of pristine samples evidenced the octahedral substitution of Sn(4+) for Ti(4+) in the TiO2 structure. In addition to the improved lithium storage behaviour of the Ti1/2Sn1/2O2 nanotubes, ex situ(119)Sn Mössbauer spectroscopy of cycled electrodes has sufficiently confirmed that no decomposition of the Ti1/2Sn1/2O2 structure occurred, and that no Li-Sn phase was formed during the discharge, corroborating that the electrochemical reaction is due exclusively to Li(+) insertion into the Ti1/2Sn1/2O2 nanotubes in the 1 ≤ U/V ≤ 2.6 voltage range

Characteristics of Li-ion micro batteries fully batch fabricated by micro-fluidic MEMS packaging

A cost-effective and reliable technology allowing extreme miniaturization of batteries into glass chips and electronic packages has been developed, employing a dispense-print process for battery electrodes and liquid electrolyte. Lithium-ion micro-batteries (active area 6 × 8 mm2, 0.15–0.3 mAh) with interdigitated electrodes were fabricated, tested and finally compared with the traditional battery architecture of stacked electrodes. Commercial graphite and lithium titanate anode as well as layered nickel cathode materials were used. All the processes for the micro-battery fabrication were established during this work; in particular the micro fluidic electrolyte filling process that allows simultaneous electrolyte supply to all cells on a planar substrate. Electrode mass reproducibility was sufficient for adequate electrode balancing. Current capability similar to the conventional face-to-face electrode configuration was achieved with interdigital electrodes that can be fabricated much easily on a substrate level. The cells were successfully cycled; several 100 cycles can be achieved. Additional results of life-time characteristics and electrochemical impedance spectroscopy are presented as well. These rechargeable micro-batteries can be used for future extremely miniaturized electronic products