Manipulating Oxygen Vacancies by K⁺ Doping and Controlling Mn²⁺ Deposition to Boost Energy Storage in β-MnO₂

Abstract

Aqueous zinc-ion batteries (ZIBs) have gained wide attention for their low cost, high safety, and environmental friendliness in recent years. β-MnO 2 , a potential cathode material for ZIBs, has been restricted by its small channels for efficient charge storage. Herein, β-MnO 2 nanorods with oxygen vacancies are fabricated by a K + -doping strategy to improve the performance of ZIBs. The assembled batteries exhibit a capacity of 468 mAh g −1 , a power density of 2605 W kg −1 , and an energy density of 179 Wh kg −1 , which outperforms most reported ZIBs. Such a performance is owing to the synergistic combination of the oxygen vacancies in β-MnO 2 and concurrent deposition of ε-MnO 2 from Mn 2+ in the electrolyte. Furthermore, superior cycling stability with negligible capacity decay in these batteries is demonstrated over 1000 cycles at a high current of 2 A g −1 . This study reveals the importance of oxygen vacancies and Mn 2+ deposition effect in understanding the mechanism of charge storage in MnO 2 -based ZIBs.

N-doped carbon fibers protection boost electrochemical performance of MnO-based cathode in rate capability and cycling-life

“…Also, the formed ZnMn2O4 (minor fragmented nanoparticles covering the surface of MnOC nanofibers) can be directly observed on the surface of the electrode at 0.9 V in Figure S13a (the atom ratio value of Zn: Mn is 1:1.16, no showing of sulfur, that differs from ZHS). What's more, the interlayer spacing of 0.271, 0.246 and 0.242 nm shown in Figure S14a, which can be indexed to ( 103) and (211) plane of ZnMn2O4 39 and the (100) plane of ε-MnO2 (also can be demonstrated by the characteristic peak of Mn-O at 645 cm -1 in Raman, Figure 5) [40][41][42][43] , respectively, certify the presence of ZnMn2O4 and MnOx. To further elucidate the energy storage process, ex-situ XPS, which can evaluate the chemical valence state of manganese in different states, was also employed.…”

Recent development of manganese dioxide-based materials as zinc-ion battery cathode

“…Wang et al prepared β-MnO 2 nanorods with oxygen vacancies by a K + doping strategy to improve the performance of ZIBs. 136 The O K -MnO 2 electrode exhibits a capacity of 468 mA h g −1 (0.1 A g −1 ), a power density of 2605 W kg −1 , and an energy density of 179 W h kg −1 , and the capacity has no obvious attenuation after 1000 cycles at 2 A g −1 , showing an excellent cycle life. This property is due to the synergistic effect of oxygen vacancy in β-MnO 2 and the Mn 2+ deposition effect.…”

Advanced In Situ Electrochemical Induced Dual‐Mechanism Heterointerface toward High‐Energy Aqueous Zinc‐Ion Batteries

“…Therefore, it is necessary to design economical and efficient Mn‐based cathode to improve the reaction kinetics and structural stability. [ 9,10 ]…”

“…Therefore, it is necessary to design economical and efficient Mn-based cathode to improve the reaction kinetics and structural stability. [9,10] In general, manipulating the surface charge state of constructed materials can improve the activity during electrochemical reactions. Recently, the surface vacancy has been proved to enhance the electrochemical performance through regulating the electronic structure of the active sites, charge density and electron transfer ability.…”