Si anodes for Li-ion batteries are notorious for their large volume expansion during lithiation and the corresponding detrimental effects on cycle life. However, calendar life is the primary roadblock for widespread adoption. During calendar life aging, the main origin of impedance increase and capacity fade is attributed to the instability of the solid electrolyte interphase (SEI). In this work, we use ex situ nano-Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy to characterize the structure and composition of the SEI layer on amorphous Si thin films after an accelerated calendar aging protocol. The characterization of the SEI on non-washed and washed electrodes shows that brief washing in dimethyl carbonate results in large changes to the film chemistry and topography. Detailed examination of the non-washed electrodes during the first lithiation and after an accelerated calendar aging protocol reveals that PF6 – and its decomposition products tend to accumulate in the SEI due to the preferential transport of PF6 – ions through polyethylene oxide-like species in the organic part of the SEI layer. This work demonstrates the importance of evaluating the SEI layer in its intrinsic, undisturbed form and new strategies to improve the passivation of the SEI layer are proposed.

Financial decisions play a critical role in today's enterprise financial management activities. Therefore, the study of financial decision support system (FDSS) is of great significance since the right business decisions can greatly improve the enterprise decision effects. Considering the above issue, we present a framework for the financial decision support system in this paper.

Gigahertz (GHz) femtosecond (fs) lasers have opened possibilities for enhancing and controlling the laser machining quality to engineer the physicochemical properties of materials. However, fundamental understanding of laser-material interactions by GHz fs laser has remained unsolved due to the complexity of associated ablation dynamics. Here, we study the ablation dynamics of copper (Cu) by GHz fs bursts using in situ multimodal diagnostics, time-resolved scattering imaging, emission imaging, and emission spectroscopy. A combination of probing techniques reveals that GHz fs bursts rapidly remove molten Cu from the irradiated spot due to the recoil pressure exerted by following fs pulses. Material ejection essentially stops right after the burst irradiation due to the limited amount of remnant matter, combined with the suppressed heat conduction into the target material. Our work provides insights into the complex ablation mechanisms incurred by GHz fs bursts, which are critical in selecting optimal laser conditions in cross-cutting processing, micro/nano-fabrication, and spectroscopy applications.

In this work, we study the ablation dynamics of copper (Cu) induced by single fs pulse and fs GHz bursts using in situ multimodal diagnostics; time-resolved scattering imaging, emission imaging, and optical emission spectroscopy. Multimodal probing techniques reveal that fs GHz bursts rapidly remove molten liquid Cu from the irradiated spot due to the recoil pressure exerted by following fs pulses. Material ejection stops after burst irradiation due to the limited amount of remnant matter, combined with the suppressed heat conduction into the target material. Our work provides insights into the complex ablation mechanisms of GHz fs bursts, which are critical in selecting optimal laser conditions in cross-cutting processing and micro/nano-fabrication applications.

Silicon-based anodes are widely expected to vastly improve the performance of lithium-ion batteries (LIBs). However, the silicon anode interface is well-known to be unstable and reactive, leading to various electrolyte side reactions that would ultimately lower the battery performance. Consequently, it is critically important to rationally design the silicon anode to stabilize its interface. The Langmuir–Blodgett (LB) technique is a well-established, versatile, and powerful method for fabricating ultrathin films over solid substrates. Here, we utilize LB approach to generate thin films composed of small organic molecules over silicon electrodes as protective layers. Such molecular layers were found capable of mediating the electrochemical behavior of silicon electrodes in both aqueous and organic carbonate electrolytes. This study illustrates the applicability of small-molecule LB films in electrode interface engineering for LIB technology development.