ChengMolecularStorageofMgIons.pdf
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Abstract
Mg batteries have potential advantages in terms of safety, cost, and reliability
over existing battery technologies, but their practical implementations are hindered
by the lack of amenable high-voltage cathode materials. The development
of cathode materials is complicated by limited understandings of the unique
divalent Mg²⁺ ion electrochemistry and the interaction/transportation of Mg²⁺
ions with host materials. Here, it is shown that highly dispersed vanadium oxide
(V₂O₅) nanoclusters supported on porous carbon frameworks are able to react
with Mg²⁺ ions reversibly in electrolytes that are compatible with Mg metal, and
exhibit high capacities and good reaction kinetics. They are able to deliver initial
capacities exceeding 300 mAh g⁻¹ at 40 mA g⁻¹ in the voltage window of 0.5 to
2.8 V. The combined electron microscope, spectroscopy, and electrochemistry
characterizations suggest a surface-controlled pseudocapacitive electrochemical
reaction, and may be best described as a molecular energy storage mechanism.
This work can provide a new approach of using the molecular mechanism for
pseudocapacitive storage of Mg²⁺ for Mg batteries cathode materials