Quantifying the Evolution of Inactive Li/Lithium Hydride and Their Correlations in Rechargeable Anode-free Li Batteries.

Electrolyte optimization, such as using fluoride-bearing electrolytes, is regarded as an effective way to improve the cycle performance of lithium metal batteries (LMBs), but the promotion mechanisms of the electrolytes are in controversy due to the lack of quantitative understanding of the reaction products during cycling. Here, taking several fluorinated electrolytes as models, we use mass spectrometry titration (MST) and solid state nuclear magnetic resonance (NMR) techniques to quantify the evolution of dead Li metal, solid electrolyte interphases (SEI) and lithium hydride (LiH) during cycling. Our quantitative results clearly disclose that lithium difluoro(oxalato)borate (LiODFB) is able to inhibit the formation of SEI and LiH while fluoroethylene carbonate (FEC) mainly inhibits the formation of dead Li metal. Furthermore, we surprisingly observe a linear correlation between LiH and SEI formation, whereas the commonly mentioned lithium fluoride (LiF) shows a weak correlation with either dead Li metal or SEI. Guided by the clear failure mechanism, we can provide a reasonable explanation for the synergistic effect with the combination of LiODFB and FEC from a quantitative perspective. We believe that a quantitative insight of electrolytes on the failure mechanism of LMBs will guide us to explore the functional electrolytes to achieve the practical application of LMBs.

Data Visualization and Analysis in Second Language Research.

I am working as both a TEFL teacher and an SLA researcher in China, doing SLA research. Recently, I have been working on new approaches to data analysis and I've found that a book titled "Data Visualization and Analysis in Second Language Research" by Dr. Guilherme D. Garcia is of great significance in empirical research in the field of SLA. This book serves only as a practical and user-friendly guide to beginners involved in SLA research, but also navigation to veteran SLA researchers devoted to new perspectives in data analysis. So far, the author has made his first attempt to connect data visualization under R to SLA research. The author reviews the previous research results and suggests some modifications through running R. From my perspective, it fills a gap in the SLA research practice-to lead readers into a new track of visualizing their reported results. Overall, to make an increasingly higher demand for SLA research, this book is particularly designated for quantitative data analysis in SLA. It is strongly recommended to write a book review to introduce readers to the realm of data visualization and help most SLA researchers better understand the potential value of R and visualization in SLA research.