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Li-O 2 battery is the leading next-generation battery system, which is known for its extremely high theoretic specific energy. However, the Li metal used in Li-O 2 batteries suffers from low Li utilization and safety hazards. In this work, as an alternative to Li anode, Li 21 Si 5 powders, which are synthesized by an easy mechanical process, are incorporated into a Li-ion oxygen battery. The electrochemical property of the prepared battery and its cycling stability are investigated. Without electrochemical prelithiation, the pursuit of Li-Si alloy anodes in this study provides an easy and scalable strategy for preparing Li-ion oxygen batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] Li-rich Mn-based oxides (LRMOs) are considered as one of the most-promising cathode materials for next generation Li-ion batteries (LIBs) because of their high energy density. Nevertheless, the intrinsic shortcomings, such as the low first coulomb efficiency, severe capacity/voltage fade, and poor rate performance seriously limit its commercial application in the future. In this work, we construct successfully g-C 3 N 4 coating layer to modify Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LMNC) via a facile solution. The g-C 3 N 4 layer can alleviate the side-reaction between electrolyte and LMNC materials, and improve electronic conduction of LMNC. In addition, the g-C 3 N 4 layer can suppress the collapse of structure and improve cyclic stability of LMNC materials. Consequently, g-C 3 N 4 (4 wt%)-coated LMNC sample shows the highest initial coulomb efficiency (78.5%), the highest capacity retention ratio (78.8%) and the slightest voltage decay (0.48 V) after 300 loops. Besides, it also can provide high reversible capacity of about 300 and 93 mAh g−1 at 0.1 and 10C, respectively. This work proposes a novel approach to achieve next-generation high-energy density cathode materials, and g-C 3 N 4 (4 wt%)-coated LMNC shows an enormous potential as the cathode materials for next generation LIBs with excellent performance. [ABSTRACT FROM AUTHOR]

We confirmed the existence of LiO 2 by electrochemical quartz crystal microbalance (EQCM) in TEGDME based Li-O 2 batteries. Our results indicated that Li 2 O 2 is generated through stepwise electrochemical reactions rather than disproportionation. We report for the first time that the formed Li 2 O 2 oxidizes to LiO 2 at relative negative potential and O 2 at positive potential respectively. Our conclusions were based on both experimental observations and quantitative analysis. This may enlighten us to reconsider the Li-O 2 batteries mechanisms in a quantitative way. [ABSTRACT FROM AUTHOR]