Department of Mechanical Engineering, Wayne State University , Detroit, Michigan 48202, United States.
Department of Biomedical Engineering and Chemistry, Boston University , Boston, Massachusetts 02115, United States.
ACS Appl Mater Interfaces. 2016 Jun 22;8(24):15242-9. doi: 10.1021/acsami.6b02620. Epub 2016 Jun 10.
Fabrication of lithium-ion batteries that operate from room temperature to elevated temperatures entails development and subsequent identification of electrolytes and electrodes. Room temperature ionic liquids (RTILs) can address the thermal stability issues, but their poor ionic conductivity at room temperature and compatibility with traditional graphite anodes limit their practical application. To address these challenges, we evaluated novel high energy density three-dimensional nano-silicon electrodes paired with 1-methyl-1-propylpiperidinium bis(trifluoromethanesulfonyl)imide (Pip) ionic liquid/propylene carbonate (PC)/LiTFSI electrolytes. We observed that addition of PC had no detrimental effects on the thermal stability and flammability of the reported electrolytes, while largely improving the transport properties at lower temperatures. Detailed investigation of the electrochemical properties of silicon half-cells as a function of PC content, temperature, and current rates reveal that capacity increases with PC content and temperature and decreases with increased current rates. For example, addition of 20% PC led to a drastic improvement in capacity as observed for the Si electrodes at 25 °C, with stability over 100 charge/discharge cycles. At 100 °C, the capacity further increases by 3-4 times to 0.52 mA h cm(-2) (2230 mA h g(-1)) with minimal loss during cycling.
制造可在室温至高温下运行的锂离子电池需要开发和随后确定电解质和电极。室温离子液体（RTILs）可以解决热稳定性问题，但它们在室温下的离子电导率差以及与传统石墨阳极的兼容性限制了它们的实际应用。为了解决这些挑战，我们评估了新型高能量密度三维纳米硅电极与 1-甲基-1-丙基哌啶双（三氟甲烷磺酰基）亚胺（Pip）离子液体/碳酸丙烯酯（PC）/LiTFSI 电解质的组合。我们观察到，PC 的添加对报告的电解质的热稳定性和可燃性没有不利影响，而在较低温度下大大改善了传输性能。硅半电池的电化学性能作为 PC 含量、温度和电流速率的函数的详细研究表明，容量随 PC 含量和温度的增加而增加，随电流速率的增加而减小。例如，在 25°C 时，添加 20% PC 可使 Si 电极的容量大幅提高，经过 100 次充放电循环后仍保持稳定。在 100°C 时，容量进一步增加 3-4 倍，达到 0.52 mA h cm(-2)（2230 mA h g(-1)），循环过程中损失最小。
