Table 2 Estimation of surface Frenkel defect concentration.

From: The critical role of point defects in improving the specific capacitance of δ-MnO2 nanosheets

Data set

Centre (Å)

Height (arb.)

Area (arb.)

FWHM (Å)

Mn-vac. (%)

Pristine MnO2

2.897

15.988

3.461

0.203

N/A

Protonated MnO2

2.858

13.896

2.826

0.191

18.3

Reassembled MnO2–pH 4

2.876

13.810

2.772

0.189

19.9

Reassembled MnO2–pH 2

2.867

12.335

2.544

0.194

26.5

  1. Gaussian parameters for the Mn–Mn in-sheet PDF peak corresponding to different samples extracted using Fityk70. Peak area is normalized to the Mn vacancy content of the parent phase KxMnO2 with the assumption that the intrinsic population is on the order of parts per million in the high-temperature crystalline phase.
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