Abstract
? 2022 Elsevier B.V.The growing demand for wearable electronics boosts researches on flexible fibrous energy storage devices, such as fibrous Zn-MnO2 battery. One bottleneck for the capacity of fibrous MnO2 electrode, especially at high discharge rate, is the inefficient interfacial charge transfer between nano particles within mechanical-mixed MnO2 aggregates. Herein, nano γ-MnO2 has been in-situ grafted on nano carbon branches via a mild interfacial oxidation reaction using KMnO4-doped MnO2 sol precursor, to form nano composites of MnO2@ hierarchical carbon networks. The grafting reaction selectively takes place at defective sites with a mixed bonding state on the surface of the carbon branches, during which a rapid δ-to-γ crystal transformation is largely boosted, instead of traditional slow δ-to-α crystal transformation. An efficient fibrous MnO2 electrode based on the composites of MnO2@ hierarchical carbon networks is successfully applied to fibrous Zn-MnO2 battery, by giving a 2.5 times of capacitance promotion and a better charging-discharging cycling stability.
NSTL
Elsevier