Electrochemical performance of highly amorphous GeOx powders synthesized in different alcohols for use in Na- and Li-ion batteries
Electrochemical performance of highly amorphous GeOx powders synthesized in different alcohols for use in Na- and Li-ion batteries
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DOI：
10.1039/c6ra20794d
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发表时间：
2016-01-01
期刊：
影响因子：
3.9
通讯作者：
Itoh, T.
中科院分区：
文献类型：
--
作者：
Kajita, T.;Itoh, T.
采用溶液合成法，将NaAGE用乙醇氧化，置于蒸馏水中，合成了高非晶态GeOX粉末。此外，我们还研究了溶液合成过程中使用的乙醇对粉末样品的Na-和Li-离子的电化学插入/提取性能的影响。我们比较了使用不同的醇进行的氧化过程。在异丙醇(仲醇)中氧化合成的非晶态Geox粉末对Na-和Li-离子的插入/提取具有良好的电化学性能，而用甲醇、乙醇和正丙醇(伯醇)合成的非晶态Geox粉末的电化学性能较差。这些粉末由大颗粒组成，这是其电化学性能较差的原因。特别是，它们在钠离子电池中的循环性能因大颗粒而显著降低。因此，在溶液合成过程中，仲醇的使用是合成高无定形、小颗粒Geox粉末的关键。最后还发现，电解液分解也是钠离子电池循环性能恶化的主要原因之一，因为在充放电过程中，钠离子电池中Geox颗粒体积的变化小于锂离子电池。
We synthesized highly amorphous GeOx powders by a solution synthesis method, in which NaGe was oxidized by alcohol and placed in distilled water. Further, we investigated the effect of the alcohol used during the solution synthesis method on the electrochemical Na- and Li-ion insertion/extraction performances of the powder sample. We compared the oxidation process as performed using various alcohols. The amorphous GeOx powder sample synthesized by oxidation in 2-propanol (secondary alcohol) exhibited good electrochemical performance with respect to Na- and Li-ion insertion/extraction, while the amorphous GeOx powders synthesized using methanol, ethanol, and 1-propanol (primary alcohol) showed poor performances. These powders consisted of large particles, which was the reason for their poor electrochemical performance. In particular, their cycling performance in a Na-ion cell was significantly lowered by the large particle size. Hence, during the solution synthesis process, the use of a secondary alcohol is the key to synthesizing highly amorphous GeOx powders with small particle sizes. Finally, electrolyte decomposition was also found to be one of the main causes for the deterioration of the cycling performance in a Na-ion cell, because the change in the volume of the GeOx particles during charging/discharging was smaller in the Na-ion cell than in a Li-ion cell.