The influence of transition metal oxides on the kinetics of Li2O2 oxidation in Li-O2 batteries: high activity of chromium oxides
The influence of transition metal oxides on the kinetics of Li2O2 oxidation in Li-O2 batteries: high activity of chromium oxides
复制标题
DOI：
10.1039/c3cp53330a
复制
发表时间：
2014-01-01
影响因子：
3.3
通讯作者：
Shao-Horn, Yang
中科院分区：
文献类型：
--
作者：
Yao, Koffi P. C.;Lu, Yi-Chun;Shao-Horn, Yang
减少与Li 2 O2电化学氧化相关的能量损失对于开发用于实际用途的高效可再充电锂-氧（Li-O-2）电池至关重要。使用Li 2 O2-预填充电极研究了一系列具有不同e（g）填充的钙钛矿对Li 2 O2氧化动力学的影响。虽然LaCrO 3在碱性溶液中水氧化时对析氧是无活性的，但发现其在所有检查的钙钛矿中提供朝向Li 2 O2氧化的最高比电流。对Cr基催化剂的进一步探索表明，具有氧化表面的平均粒径为40 nm的Cr纳米颗粒（Cr NP）具有与LaCrO 3相当的表面积活性，但具有更大的质量活性。与Pt/C和Ru/C促进电解质氧化以及Li 2 O2氧化不同，没有发现Cr NP相对于Vulcan碳增强电解质氧化的证据。在O K和Cr L边缘的X射线吸收光谱显示，在Li 2 O2氧化后，Cr NP表面上的Cr 3 + Cr 6+的氧化还原过程，这可能是负责增强Li 2 O2的氧化动力学和降低的Li-O-2电池的充电电压。
Reducing the energy loss associated with Li2O2 electrochemical oxidation is paramount to the development of efficient rechargeable lithium-oxygen (Li-O-2) batteries for practical use. The influence of a series of perovskites with different e(g) filling on the kinetics of Li2O2 oxidation was examined using Li2O2-prefilled electrodes. While LaCrO3 is inactive for oxygen evolution upon water oxidation in alkaline solution, it was found to provide the highest specific current towards Li2O2 oxidation among all the perovskites examined. Further exploration of Cr-based catalysts showed that Cr nanoparticles (Cr NP) with an average particle size of 40 nm, having oxidized surfaces, had comparable surface area activities to LaCrO3 but much greater mass activities. Unlike Pt/C and Ru/C that promote electrolyte oxidation in addition to Li2O2 oxidation, no evidence of enhanced electrolyte oxidation was found for Cr NP relative to Vulcan carbon. X-ray absorption spectroscopy at the O K and Cr L edge revealed a redox process of Cr3+ Cr6+ on the surface of Cr NP upon Li2O2 oxidation, which might be responsible for the enhanced oxidation kinetics of Li2O2 and the reduced charging voltages of Li-O-2 batteries.