A Novel MnO-Graphite Dual-ion Battery and New Insights into Its Reaction Mechanism during Initial Cycle by Operando Techniques.

Dual ion battery complements lithium ion batteries in terms of the use of inexpensive materials and ease to construct cells. To improve the safety and energy density of dual ion battery, in this paper, a novel MnO-graphite dual-ion battery is reported for the first time. Microporous MnO materials is used as the anode, which exhibits a low conversion potential and low voltage hysteresis. The MnO/graphite dual-ion battery can deliver a capacity of 104 mAhg-1 at 0.5 C and exhibits good rate performances and cycling stability (capacity retention > 93 % after 300 cycles). A mechanism is proposed to explain the irreversibility in capacity during the initial cycle by using operando X-ray diffraction in combination with online electrochemical mass spectrometry and electrochemical impedance spectroscopy.