creator Shi, Zhepu 2018 Fall 2018 Thesis Illinois Institute of Technology MMAE / Mechanical, Materials, and Aerospace Engineering advisor Shaw, Leon Materials Science ball milling carbon coating cycle stability electrochemical performance heat treatment NaCrO2 en In this study, we report the effects of carbon coating on the electrochemical cycle stability of Na-ion batteries made of NaCrO2 cathodes. Various coating approaches and conditions have been investigated for 10-h high energy ball milled NaCrO2. It is shown that mixing the carbon source with NaCrO2 particles before the high-temperature carbonization reaction is a critical step. The solution-based mixing of the carbon source with NaCrO2 leads to the best carbon coating uniformity. Furthermore, carbonization treatment should be limited to 10 min at 650 ℃ in order to prevent the reaction between carbon and NaCrO2 to form chromium carbides. Uniform carbon coating can improve the capacity retention of NaCrO2 over charge/discharge cycles and the best capacity retention achieved in this study is 70% after 50 cycles. Furthermore, once the coating is uniformly distributed, NaCrO2 exhibits a very high specific capacity (140 mAh/g) which is significantly higher than the typical value of 110 mAh/g reported in the literature. The unusually high specific capacity observed is attributed to the enhancement of Na-ion intercalation and de-intercalation rates at the electrode/electrolyte interface because of the presence of the carbon coating. born digital application/pdf In Copyright http://rightsstatements.org/page/InC/1.0/ Restricted Access http://hdl.handle.net/10560/islandora:1001306