Differences in Interfacial Reactivity of Graphite and Lithium Metal Battery Electrodes Investigated Via Operando Gas Analysis.

Gases evolved from lithium batteries can drastically affect their performance and safety; for example, cell swelling is a serious safety issue. Here, we combine operando pressure measurements and online electrochemical mass spectrometry measurements to identify the nature and quantity of gases formed in batteries with graphite and lithium metal electrodes. We demonstrate that ethylene, a main gas evolved in SEI formation reactions, is quickly consumed at lithium metal electrodes unless they have been pretreated in the electrolyte.

Combined Electrochemical, XPS, and STXM Study of Lithium Nitride as a Protective Coating for Lithium Metal and Lithium-Sulfur Batteries.

LiN is an excellent protective coating material for lithium electrodes with very high lithium-ion conductivity and low electronic conductivity, but the formation of stable and homogeneous coatings is technically very difficult. Here, we show that protective LiN coatings can be simply formed by the direct reaction of electrodeposited lithium electrodes with N gas, whereas using battery-grade lithium foil is problematic due to the presence of a native passivation layer that hampers that reaction. The protective LiN coating is effective at preventing lithium dendrite formation, as found from unidirectional plating and plating-stripping measurements in Li-Li cells.

Solvothermal synthesis of nanoscale BaTiO in benzyl alcohol-water mixtures and effects of manganese oxide coating to enhance the PTCR effect.

A solvothermal method using various benzyl alcohol/water solvent mixtures has been used to synthesise phase pure nanocrystalline BaTiO samples with varying particle sizes in the range of 11-139 nm. The crystallite/particle size of BaTiO shows an overall decrease as the benzyl alcohol percentage increases, especially at higher percentages (≥80%) of benzyl alcohol. The decrease in crystallite/particle size can be attributed to the increased viscosity of the solvent mixture when raising the percentage of benzyl alcohol.

Two electrolyte decomposition pathways at nickel-rich cathode surfaces in lithium-ion batteries.

Preventing the decomposition reactions of electrolyte solutions is essential for extending the lifetime of lithium-ion batteries. However, the exact mechanism(s) for electrolyte decomposition at the positive electrode, and particularly the soluble decomposition products that form and initiate further reactions at the negative electrode, are still largely unknown. In this work, a combination of gas measurements and solution NMR was used to study decomposition reactions of the electrolyte solution at NMC (LiNi Mn Co O) and LCO (LiCoO) electrodes.