Tips-Bundled Pt/Co₃O₄ Nanowires with Directed Peripheral Growth of Li₂O₂ as Efficient Binder/Carbon-Free Catalytic Cathode for Lithium–Oxygen Battery

We propose a new design of a binder/carbon-free air electrode with tips-bundled Pt/Co₃O₄ nanowires grown directly on Ni foam substrate. In this design, the side reactions related to binder/carbon are excluded. The presence of Pt not only promotes the formation of the tips-bundled structure of Co₃O₄ nanowires but also directs the uniform deposition of a fluffy, thin Li₂O₂ layer only on the periphery of Pt/Co₃O₄ nanowires. This crystallization habit of Li₂O₂ makes it easy to decompose upon recharge with reduced side reactions. As a result, Li–O₂ batteries with this cathode show low polarization

Preferential <i>c</i>‑Axis Orientation of Ultrathin SnS₂ Nanoplates on Graphene as High-Performance Anode for Li-Ion Batteries

A SnS₂/graphene (SnS₂/G) hybrid was synthesized by a facile one-step solvothermal route using graphite oxide, sodium sulfide, and SnCl₄·5H₂O as the starting materials. The formation of SnS₂ and the reduction of graphite oxide occur simultaneously. Ultrathin SnS₂ nanoplates with a lateral size of 5–10 nm are anchored on graphene nanosheets with a preferential (001) orientation, forming a unique plate-on-sheet structure. The electrochemical tests showed that the nanohybrid exhibits a remarkably enhanced cycling stability and rate capability compared with bare SnS₂. The excellent electrochemical properties of SnS₂/G could be ascribed to the in situ introduced graphene matrix which offers two-dimensional conductive networks, disperses and immobilizes SnS₂ nanoplates, buffers the volume changes during cycling, and directs the growth of SnS₂ nanoplates with a favorable orientation

Understanding Moisture and Carbon Dioxide Involved Interfacial Reactions on Electrochemical Performance of Lithium–Air Batteries Catalyzed by Gold/Manganese-Dioxide

Lithium–air (Li–air) battery works essentially based on the interfacial reaction of 2Li + O₂ ↔ Li₂O₂ on the catalyst/oxygen-gas/electrolyte triphase interface. Operation of Li–air batteries in ambient air still remains a great challenge despite the recent development, because some side reactions related to moisture (H₂O) and carbon dioxide (CO₂) will occur on the interface with the formation of some inert byproducts on the surface of the catalyst. In this work, we investigated the effect of H₂O and CO₂ on the electrochemical performance of Li–air batteries to evaluate the practical operation of the batteries in ambient air. The use of a highly efficient gold/δ-manganese-dioxide (Au/δ-MnO₂) catalyst helps to understand the intrinsic mechanism of the effect. We found that H₂O has a more detrimental influence than CO₂ on the battery performance when operated in ambient air. The battery operated in simulated dry air can sustain a stable cycling up to 200 cycles at 400 mA g^–1 with a relatively low polarization, which is comparable with that operated in pure O₂. This work provides a possible method to operate Li–air batteries in ambient air by using optimized catalytic electrodes with a protective layer, for example a hydrophobic membrane