期刊
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
卷 933, 期 -, 页码 -出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jelechem.2023.117190
关键词
High voltage cathode; LiCoO2; Surface coating; Single particle; Lithium-ion battery
Surface coating is a key approach to improve the high-rate performance and stability of lithium-ion batteries (LIBs). In this study, Al-Ti oxide coated LiCoO2 (LCO) materials were synthesized and their electrochemical properties were compared to pristine LCO. The results showed that the Al-Ti@ LCO had higher discharge capacity, more stable cycling ability, and increased high voltage rate capability. The Al-Ti oxide coating also reduced charge transfer resistance and minimized degradation of the active material during long cycling. The findings indicate that the Al-Ti oxide coating contributes to the enhancement of electrochemical performance without hindering lithium-ion diffusion.
Surface coating is a key approach for lithium-ion batteries (LIBs) to improve the high-rate performance and stability of batteries. LiCoO2 (LCO) has been one of the promising cathode materials in LIBs due to its high the-oretical capacity of 274 mAh/g and high theoretical density (5.1 g cm-3) of material. However, the capacity used is only 140 mAh/g (-50 % of theoretical capacity) under the voltage condition limited to 4.2 V. Increasing the operation voltage is the prime way to increase the energy density of the LCO electrode. In this study, we synthesize the pristine and Al-Ti oxide coated LCO materials by simple, cost-effective and eco-friendly sol-gel method and its intrinsic parameters are measured by single particle measurement (SPM) technique. A quanti-tative evaluation of the electrochemical properties of the active material shows a clear difference between pris-tine LCO and Al-Ti@ LCO. The measured rate characteristics show that Al-Ti@ LCO has higher discharge capacity under the same current rate condition and stable cycling ability. The high voltage rate capability of LCO is exponentially increased with Al-Ti oxide coating with the highest retention of 96 % after 50 cycles within 3.0-4.5 Vat 4.2C. From Tafel plot analysis the charge transfer resistance (RCT) of Al-Ti@ LCO was lower in all DOD states than pristine LCO. Also, to investigate mass transfer properties, GITT was carried out. The Al -Ti oxide coating is believed to make the LCO electrode more resistant to interfacial side reactions and fast struc-tural degradation at high voltage and thus reduce the degradation of active material within long cycling. This result shows Al-Ti oxide coating layer contributes to the enhancement of electrochemical performance without interfering with lithium-ion diffusion.
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