Revealing molecular-level surface redox sites of controllably oxidized black phosphorus nanosheets

Nakhanivej Puritut^1,11,Yu Xu^1,10,11, Park Sul Ki1, Kim Soo^2,3, Hong Jin-Yong^4,5, Kim Hae Jin⁶, Lee Wonki⁷, Hwang Jun Yeon⁷, Yang Ji Eun⁸, Wolverton Chris², Kong Jing⁴, Chhowalla Manish⁸, Park Ho Seok^1,9*

¹School of Chemical Engineering, College of Engineering, Sungkyunkwan University, Suwon, Republic of Korea

¹⁰School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, China.

¹¹These authors contributed equally: Puritut Nakhanivej, Xu Yu

Abstract: Bulk and two-dimensional black phosphorus are considered to be promising battery materials due to their high theoretical capacities of 2,600 mAh g⁻¹. However, their rate and cycling capabilities are limited by the intrinsic (de-)alloying mechanism. Here, we demonstrate a unique surface redox molecular-level mechanism of P sites on oxidized black phosphorus nanosheets that are strongly coupled with graphene via strong interlayer bonding. These redox-active sites of the oxidized black phosphorus are confined at the amorphorized heterointerface, revealing truly reversible pseudocapacitance (99% of total stored charge at 2,000 mV s⁻¹). Moreover, oxidized black-phosphorus-based electrodes exhibit a capacitance of 478 F g^–1(four times greater than black phosphorus) with a rate capability of ~72% (compared to 21.2% for black phosphorus) and retention of ~91% over 50,000 cycles. In situ spectroelectrochemical and theoretical analyses reveal a reversible change in the surface electronic structure and chemical environment of the surface-exposed P redox sites.

(a) Schematic model of the foBG film showing adsorption sites, charge storage and charge transfer mechanism; (b) Rate capability of 2D BP, rGO, oBGO and foBG at various current densities from 1 to 50 A g^–1.

Nature Materials,2019, 18, 156-162;Doi:10.1038/s41563-018-0230-2.IF: 39.235

链接：https://www.nature.com/articles/s41563-018-0230-2