Ultrathin Al2O3 Coatings for Improved Cycling Performance and Thermal Stability of LiNi0.5Co0.2Mn0.3O2 Cathode Material

• Published in: Electrochimica acta Vol. 203; no. C; pp. 154 - 161
• Main Authors: Shi, Yang, Zhang, Minghao, Qian, Danna, Meng, Ying Shirley
• Format: Journal Article
• Language: English
• Published: United Kingdom Elsevier Ltd 10.06.2016; Elsevier
• Subjects: ALD coating; High voltage Cyclability; LiNi0.5Co0.2Mn0.3O2; Lithium-ion battery; Thermal stability; Lithium-ion battery; High voltage Cyclability; ALD coating; Thermal stability; LiNi0.5Co0.2Mn0.3O2
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2016.03.185

•Ultrathin Al2O3 coatings are deposited on LiNi0.5Co0.2Mn0.3O2 composite electrodes by Atomic Layer Deposition.•The Al2O3 coating effectively improves cycling performance in high voltage ranges.•The Al2O3 coating decreases charge transfer resistance and enhances Li ion diffusivity.•The Al2O3 coating increases thermal stability and delays exothermic reactions Ultrathin Al2O3 is directly deposited on LiNi0.5Co0.2Mn0.3O2 (NCM523) composite electrodes by atomic layer deposition (ALD). After 4 ALD cycles, the coated cathode exhibits significantly improved cycling performance and thermal stability, especially at high working voltage. The capacity retention of the coated cathode is 76.8% after 30 cycles in the voltage range of 2–4.8V, compared to 58.4% of pristine cathode. The exothermic peak in differential scanning calorimetry (DSC) analysis, corresponding to the reactions between delithiated electrode and electrolyte, is also delayed after cycling. The improvement is attributed to the reduced charge transfer resistance and enhanced Li ion diffusivity, as the Al2O3 coating may suppress the side reactions between electrode and electrolyte, and inhibit the oxygen release under high operating voltage.