Engineering lithium-ion battery cathodes for high-voltage applications using electromagnetic excitation
Engineering lithium-ion battery cathodes for high-voltage applications using electromagnetic excitation
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DOI：
10.1007/s10853-020-04871-5
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发表时间：
2020-05
影响因子：
4.5
通讯作者：
Laisuo Su;S. Jha;X. L. Phuah;Jianghong Xu;Nathan Nakamura;Haiyan Wang;J. Okasinski;B. Reeja‐Jayan
中科院分区：
文献类型：
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作者：
Laisuo Su;S. Jha;X. L. Phuah;Jianghong Xu;Nathan Nakamura;Haiyan Wang;J. Okasinski;B. Reeja‐Jayan
微波辐射（MWR）是一种电磁激发源，与传统的合成方法相比，它可以降低合成温度和化学反应的处理时间。最近，我们证明了与传统方法相比，MWR可以设计具有不同晶相的陶瓷[材料化学杂志A5，35（2017）]。在本研究中，我们进一步应用微波辐射辅助技术，通过工程化的TiO 2和ZrO 2陶瓷涂层来改善LiCoO 2阴极的电化学性能。电化学测试表明，TiO 2涂层提高了LiCoO 2电极的倍率性能。TiO 2和ZrO 2涂层均提高了LiCoO 2的高压（4.5 V）循环稳定性。经40次循环后，TiO 2涂层和ZrO 2涂层的剩余容量分别从52.8%提高到84.4%和81.9%。我们比较这些结果与现有的研究，采用传统的方法来工程TiO 2/ZrO 2的LiCoO 2，并发现，MWR辅助的方法表现出更好的性能改善。X射线光电子能谱测量表明，改善的循环稳定性来自金属氟化物的形成，保护电极与电解质的副反应。这一机制进一步支持减少从TiO 2/ZrO 2涂层LiCoO 2电极循环后的Co溶解。这项研究提供了一个新的工具箱，有助于将许多精细的低熔点材料（如聚合物）集成到电池电极中。
Microwave radiation (MWR), a type of electromagnetic excitation source, reduces the synthesis temperature and processing time for chemical reactions compared to traditional synthesis methods. Recently, we demonstrated that MWR can engineer ceramics with different crystal phases compared to traditional methods [Journal of Materials Chemistry A5, 35 (2017)]. In this study, we further apply the MWR-assisted technique to improve the electrochemical performance of LiCoO2cathodes by engineering TiO2and ZrO2ceramic coatings. Electrochemical tests suggest that the TiO2coating improves the rate capability of the LiCoO2electrode. Both TiO2and ZrO2coatings improve the high-voltage (4.5 V) cycling stability of LiCoO2. The capacity remaining is improved from 52.8 to 84.4% and 81.9% by the TiO2coating and the ZrO2coating, respectively, after 40 cycles. We compare these results with existing studies that apply traditional methods to engineer TiO2/ZrO2on LiCoO2, and find that the MWR-assisted method shows better performance improvement. X-ray photoelectron spectroscopy measurements suggest that the improved cycling stability arises from the formation of metal fluorides that protect the electrode from side reactions with electrolytes. This mechanism is further supported by the reduced Co dissolution from TiO2/ZrO2-coated LiCoO2electrode after cycling. This study provides a new toolbox facilitating the integration of many delicate, low melting point materials like polymers into battery electrodes.