understanding of the material synthesis/ fabrication, interfacial behavior, and thermal-chemical stabilities are vital. [3] With electronic appliances requiring stable voltage delivery, the current LIBs employ graphite or mixtures with soft carbons (carbon black) to achieve stable performance at discharge curves. [4] Since 1991, various forms of ordered and disordered (i.e., soft and hard) carbon have been primarily used as anode materials. [5] With graphitic carbon, a compromise was identified, which delivered a theoretical maximum capacity of 372 mAh g −1 , while maintaining stability and cycling characteristics. This stability comes at a cost of battery capacity, as it takes six carbon atoms to bind a single lithium ion (LiC 6 ) during charging process. [6] By contrast, alternative anode materials such as silicon, can bind about four lithium atoms (SiLi 4.4 ), improving energy densities by an order of magnitude. [7] Silicon anodes have garnered huge attention as they provide over ten times more theoretical capacity (3579 mAh g −1 ) than graphite anode. Problematically, the intercalated Si, Li 3.75 Si, swells in volume by about 320% during charging. Such huge volumetric expansion causes large material stresses, resulting in anode cracking, fracturing, loss of electrical contact (delamination), unstable solid electrolyte interface (SEI) and even catastrophic cell failure. [8][9][10][11] Naturally, this is unacceptable for practical and industrial applications. To overcome the capacity limitations of carbon, and the mechanical limitations of silicon, manufacturers have moved into composite materials-with the primary structure consisting of graphitic carbon, with silicon nanoparticles implanted within. First reported by Yoshio and co-workers in 2002, the C/Si composites did improve capacity, but the silicon nanoparticles were difficult to merge with the carbon bulk. [12,13] After repeated cycling, it was found that the particles separate and capacity drops. [14] Li et al. reported fabrication of graphite-Si composite using polymer blends of poly(diallyl dimethyl-ammonium chloride) and poly(sodium 4-styrenesulfonate) to obtain capacity of 450 mAh g −1 with 95% capacity retention after 200 cycles. [15] Zhang et al. prepared core-shell structure (Si@C) using silicon nanoparticles (Si-NPs) and emulsion polymerization of acrylonitrile, followed by pyrolysis. [16] The composite [15] retained A composite anode material synthesized using silicon nanoparticles, micrometer sized graphite particles, and starch-derived amorphous carbon (GCSi) offers scalability and enhanced electrochemical performance when compared to existing graphite anodes. Mechanistic elucidation of the formation steps of tailored GCSi composite are achieved with environmental transmission electron microscopy (ETEM) and thermal safety aspects of the composite anode are studied for the first time using specially designed multimode calorimetry for coin cell studies. Electrochemical analysis of the composite anode demonstrates a high initial discharge capaci...

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Temperature rise in Lithium-ion batteries (LIBs) due to solid electrolyte interfaces breakdown, uncontrollable exothermic reactions in electrodes and Joule heating can result in the catastrophic failures such as thermal runaway, which is calling for reliable real-time electrode temperature monitoring. Here, we present a customized LIB setup developed for early detection of electrode temperature rise during simulated thermal runaway tests incorporating a modern additive manufacturing-supported resistance temperature detector (RTD). An advanced RTD is embedded in a 3D printed polymeric substrate and placed behind the electrode current collector of CR2032 coin cells that can sustain harsh electrochemical operational environments (acidic electrolyte without Redox, short-circuiting, leakage etc.) without participating in electrochemical reactions. The internal RTD measured an average 5.8 °C higher temperature inside the cells than the external RTD with almost 10 times faster detection ability, prohibiting thermal runaway events without interfering in the LIBs’ operation. A temperature prediction model is developed to forecast battery surface temperature rise stemming from measured internal and external RTD temperature signatures.

In situ replenishment of formation cycle lithium-ion loss is considered for the development of longer-lasting rechargeable batteries, containing a thin lithium reservoir-electrode to mitigate the formation cycle capacity loss. Synchronized lithium and lithium-ion batteries (SLLIB) deliver specific charge-discharge capacities of 147/145 mAh g-1 for mesocarbon microbeads (MCMB) versus LiFePO 4 and 186/171 mAh g-1 for C-Si versus LiNi 1/3 Mn 1/3 Co 1/3 O 2 at 0.2 C. The energy-reduced cells (due to solid electrolyte interface (SEI) formation) are replenished and achieved an increased energy density of

The 11B—19F spin–spin coupling constant in AgBF4 is shown to have an opposite sign in water from that found in a number of organic solvents. Application of the hypothesis of Bell and Danyluk indicates that it has a positive sign in water. Evidence is presented for association, probably in the form of solvent-separated ion pairs, in aqueous LiBF4 and NaBF4 solutions, and for the formation of more tightly bound ion pairs in solvents of lower dielectric constant. In contrast, there apparently is no solute association in AgBF4 solutions in water, DMSO, DMF, or acetonitrile. The pronounced changes observed in the 11B—19F coupling constant support the postulate that its small size is a result of near cancellation of large opposing terms.The collapse of the 10B—11B isotope shift at high temperatures in the 19F spectra of solutions of AgBF4 in acetonitrile and in acetone provides evidence for exchange of fluorine among boron atoms; a mechanism is proposed for this process.