Monolayer germanium monochalcogenides (GeS/GeSe) as cathode catalysts in nonaqueous Li-O2 batteries.
Monolayer germanium monochalcogenides (GeS/GeSe) as cathode catalysts in nonaqueous Li-O2 batteries.
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DOI：
10.1039/c7cp04044j
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发表时间：
2017-08
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影响因子：
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通讯作者：
Yujin Ji;Huilong Dong;Mingye Yang;Tingjun Hou;Youyong Li
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文献类型：
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作者：
Yujin Ji;Huilong Dong;Mingye Yang;Tingjun Hou;Youyong Li
新型正极催化剂的开发对非水锂氧电池的实用化具有重要意义。本文通过第一性原理计算，揭示了单层锗单硫族化合物（2D-GeXs，X = S/Se）作为阴极催化材料的催化机理，并对其催化活性进行了评价。对于2D-GeX，具有环状结构的Li 4 O 4是最终的放电产物。自由能图表明2D-GeSe比2D-GeS在能量上更有利，这是由于其显著较低的氧还原反应（ORR）过电位（0.94 V）和析氧反应（OER）过电位（1.30 V），这源于其与LiO 2的较弱结合和与插入的Li原子的较强结合。电子性质分析表明，Li_4O_4在2D-GeSe上的最终产物诱导了半导体向半金属的转变。我们的研究结果表明，2D-GeSe是一个很好的候选人作为正极材料在非水锂-氧电池，而2D-GeS是不合适的。
The development of novel cathode catalysts is of great importance to the practical applications of nonaqueous lithium oxygen (Li-O2) batteries. Here by using first-principles calculations, we revealed the catalytic mechanism and evaluated the catalytic activity of monolayer germanium monochalcogenides (2D-GeXs, X = S/Se) as cathode catalytic materials. For 2D-GeXs, Li4O4 with a ring-like structure is the final discharge product. The free energy diagram demonstrates that 2D-GeSe is more energetically favorable than 2D-GeS due to its considerably lower oxygen reduction reaction (ORR) overpotential (0.94 V) and oxygen evolution reaction (OER) overpotential (1.30 V), which originate from its weaker binding with LiO2 and stronger binding with the inserted Li atom. The analyses on electronic properties elucidate that the final product of Li4O4 on 2D-GeSe induces the semiconductor to semi-metal transition. Our results reflect that 2D-GeSe is an excellent candidate as a cathode material in nonaqueous Li-O2 batteries, while 2D-GeS is not appropriate.