期刊
ADVANCED MATERIALS
卷 32, 期 50, 页码 -出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/adma.202005182
关键词
cathode materials; global oxygen migration; high‐ voltage cycling; hybrid redox; Li‐ ion batteries; lithium cobalt oxides
类别
资金
- Watt Energy Technology Lab gift fund
- DOE Office of Science [DE-SC0012704]
- National Science Foundation under NSF [1541959]
Cycling LiCoO2 to above 4.5 V for higher capacity is enticing; however, hybrid O anion- and Co cation-redox (HACR) at high voltages facilitates intrinsic O-alpha(-) (alpha < 2) migration, causing oxygen loss, phase collapse, and electrolyte decomposition that severely degrade the battery cyclability. Hereby, commercial LiCoO2 particles are operando treated with selenium, a well-known anti-aging element to capture oxygen-radicals in the human body, showing an anti-aging effect in high-voltage battery cycling and successfully stopping the escape of oxygen from LiCoO2 even when the cathode is cycled to 4.62 V. Ab initio calculation and soft X-ray absorption spectroscopy analysis suggest that during deep charging, the precoated Se will initially substitute some mobile O-alpha(-) at the charged LiCoO2 surface, transplanting the pumped charges from O-alpha(-) and reducing it back to O2- to stabilize the oxygen lattice in prolonged cycling. As a result, the material retains 80% and 77% of its capacity after 450 and 550 cycles under 100 mA g(-1) in 4.57 V pouch full-cells matched with a graphite anode and an ultralean electrolyte (2 g Ah(-1)).
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