Rational Design of 2D Manganese Phosphate Hydrate Nanosheets as Pseudocapacitive Electrodes
Nkosi, Funeka P.
Ozoemena, Kenneth I.
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Materials Science and Engineering Program
Embargo End Date2020-11-19
Permanent link to this recordhttp://hdl.handle.net/10754/660588
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AbstractA new class of 2D nanosheets of nitrogen-integrated phosphate-rich ammonium manganese phosphate hydrate, (NH4MnPO4·H2O) (AMP), has been developed as pseudocapacitive electrode materials. The optimized electrodes exhibited device capacitances of 48.4 and 65.4 F/g for symmetric and asymmetric configurations, respectively. The devices showed excellent energy and power (e.g., 29.4 Wh/kg and 133 kW/kg for asymmetric cells) with extraordinary capacitance retention (e.g., >93%, 100â000 cycles at 5 A/g for asymmetric cells) that surpass those of most of the reported values. The huge pseudocapacitance of AMP is attributed to several factors, including the electroactive sites containing NH4 + ions, the conductive inorganic layers, intercalated water interactions of Mn2+···H2O, redox-active phosphate ions, and the 2D nanosheets. AMP-based all-solid-state flexible asymmetric devices exhibited >95% capacitance retention upon 1000 repetitive charge-discharge cycles. This study opens doors to elegant strategies of unlocking the rich physicoelectrochemical properties of 2D AMP for next-generation pseudocapacitors.
CitationRaju, K., Han, H., Velusamy, D. B., Jiang, Q., Yang, H., Nkosi, F. P., … Ozoemena, K. I. (2019). Rational Design of 2D Manganese Phosphate Hydrate Nanosheets as Pseudocapacitive Electrodes. ACS Energy Letters, 23–30. doi:10.1021/acsenergylett.9b02299
SponsorsThis work was supported by the South Africa’s Council for Scientific and Industrial Research (CSIR), the National Research Foundation (NRF, Grant No. 113638), as well as the University of the Witwatersrand.
PublisherAmerican Chemical Society (ACS)
JournalACS Energy Letters