Modulating Anion Redox Activity of Li₁.₂Mn0.54Ni₀.₁₃Co₀.₁₃O₂ through Strong Sr−O Bonds toward Achieving Stable Li-Ion Half-/Full-Cell Performance

• Main Authors: Murugan, Vivekanantha, Arul Saravanan, Raaju Sundhar, Thangaian, Kesavan, Partheeban, Thamodaran, Aravindan, Vanchiappan, Srinivasan, Madhavi, Sasidharan, Manickam, Bharathi, K. Kamala
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Materials; Suppressed Anion Redox; Lithium-Rich Cathode; Strontium Doping; Layered to Spinel Phase Transformation; Full Cell Performance
• Online Access: https://hdl.handle.net/10356/156519
• Institution: Nanyang Technological University

Controlled synthesis and compositional modification of Li-rich layered oxides (LLOs) Li1.2Mn0.54Co0.13Ni0.13O2 is considered as a potential strategy to achieve high structural stability/reversibility, suppressed voltage/capacity fading, and realize stable cycle life performance in lithium-ion batteries (LIBs). In this study, the effect of strontium (Sr2+) doping in Li1.2−2xSrxMn0.54Co0.13Ni0.13O2 (0.0015 ≤ x ≤ 0.007) is systematically investigated by electrochemical studies. X-ray refinement studies reveal the occupancy of Sr2+ at Li+ (lithium) sites with larger oxygen-lithium-oxygen inter-slab spacing in crystal structure. Investigation of Sr2+ doped materials in Li-ion cell furnishes up to ~50% reduction in anionic redox activity during the first charge cycle compared to LLO. Ex-situ structural analysis of LLO and Sr2+−doped samples shows suppressed layered to spinel phase transformation for the latter. The Sr2+− doped electrode (x=0.005) delivers ~70 Wh kg−1 more energy (620 Wh kg−1) than the LLO at 0.2C. Besides, testing for 500 cycles at 1C, Sr2+−doped cathode (x=0.005) retains ~94% of its initial capacity as against LLO (68%). High temperature study at 55 °C shows better electrochemical performance indicating good structural stability of Sr2+−doped samples. Moreover, in full-cell configuration, Sr2+−doped cathode (x=0.005) retains ~98% of its initial capacity at 0.5C after 50 cycles unlike LLO (55%).