Dissociation of (Li 2 O 2 ) 0,+ on graphene and boron-doped graphene: insights from first-principles calculations

Reducing charge overpotential is of great significance to enhance the efficiency and cyclability of Li–O 2 batteries. Here, a dramatically reduced charge overpotential via boron-doped graphene as a catalytic substrate is successfully predicted. By first-principles calculations, from the perspective...

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Veröffentlicht in:Physical chemistry chemical physics : PCCP 2020-01, Vol.22 (25), p.14216-14224
Hauptverfasser: Hou, Binpeng, Lei, Xueling, Zhong, Shuying, Sun, Baozhen, Ouyang, Chuying
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Sprache:eng
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Zusammenfassung:Reducing charge overpotential is of great significance to enhance the efficiency and cyclability of Li–O 2 batteries. Here, a dramatically reduced charge overpotential via boron-doped graphene as a catalytic substrate is successfully predicted. By first-principles calculations, from the perspective of reaction thermodynamics and kinetics, the results show that the electrochemical oxidation of the Li 2 O 2 + cation is easier than the chemical oxidation of the neutral Li 2 O 2 molecule, and the oxidation of (Li 2 O 2 ) 0,+ is facilitated by boron-doping in pristine graphene. More importantly, the results reveal the oxidation mechanism of (Li 2 O 2 ) 0,+ : two-step dissociation with the LiO 2 molecule as a reactive intermediate has advantages over one-step dissociation; the rate-determining step for the dissociation of (Li 2 O 2 + ) G is the oxygen evolution process, while the lithium removal process is the rate-determining step for the dissociation of (Li 2 O 2 0 ) G , (Li 2 O 2 0 ) BG , and (Li 2 O 2 + ) BG .
ISSN:1463-9076
1463-9084
DOI:10.1039/d0cp02597f