Enhancing Charge/Discharge Cycle Stability of NaCrO2 Cathode for Na-Ion Batteries via Carbon Coatings
Abstract
In this study, we report the effects of carbon coating on the electrochemical cycle stability of Na-ion batteries made of NaCrO 2 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 °C 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.
- Publication:
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Masters Thesis
- Pub Date:
- 2018
- Bibcode:
- 2018MsT.........66S
- Keywords:
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- Materials science;Engineering