Facilitating Mg2+ diffusion in high potential LixV2(PO4)3 cathode material with a co-insertion strategy for rechargeable Mg-ion batteries

Ultrafast cathode characteristics of a nano-V2(PO4)3 carbon composite for rechargeable magnesium batteries

“…On the other hand, the co-insertion of Li + and Mg 2+ into the V 2 (PO 4 ) 3 framework realized a high reversible capacity of 120 mA h g −1 at 100 mA g −1 (0.76C-rate) at room temperature. 42 This enhancement could be due to the improved Mg 2+ diffusion in the solid state because of the concerted Li + /Mg 2+ insertion, as was also reported for the Chevrel Mo 6 S 8 in Li + /Mg 2+ electrolytes. However, to the best of our knowledge, the charge–discharge rate of V 2 (PO 4 ) 3 based on pure Mg 2+ insertion/extraction has not reached the anticipated level (a rate of approximately 1/2C-rate), as initially predicted by DFT calculations.…”

“…These results indicate that the crystal structure of VP was amorphized during long-term Mg 2+ insertion/extraction to ultimately result in a low exhibited capacity. To prevent the collapse of the crystal structure and maintain the exhibited capacity, three approaches could be followed in future research: (1) synthesize an amorphous Mg cathode similar to FePO 4 , 25,54 (2) use the coinsertion of dual carriers (Mg 2+ and Li + /Na + ) to prevent the crystal structure from undergoing drastic changes, 42,55 and (3) use a Mg cathode with a low Mg 2+ diffusion barrier similar to NaMn 4 O 8 . 38…”

“…24 However, analysis of the charge-discharge mechanisms of Mg x V 2 (PO 4 ) 3 has been limited to intermittent observations of the phase transition, and valence changes of vanadium in V 2 (PO 4 ) 3 using ex situ XRD/X-ray absorption ne structure (XAFS) analysis at a few states-of-charge (SOCs). 24,42 A precise understanding of the reaction behavior of Mg x V 2 (PO 4 ) 3 would require in situ XRD and in situ XAFS to be performed at a large number of SOCs.…”

Interface Polarization Effects Enhancing Mn2O3@TiO2@MXene Heterostructures for Aqueous Magnesium Ion Capacitors: Guided Charge Distribution and Transportation via Built‐in Electric Fields

“…The relevant literature is listed in Table S2 (Supporting Information). [34][35][36][37][38][39][40][41][42][43][44][45] To further investigate the influence of MXene on the electrochemical kinetics, we obtained CV curves of mesoporous Mn 2 O 3 and mesoporous Mn 2 O 3 @TiO 2 @MXene at different scan rates (0.2-1.0 mV s À1 ) in a three-electrode cell system (Figure 5a and S11a, Supporting Information). Both materials exhibit characteristics of two oxidation peaks and two reduction peaks.…”

Cathode Materials and Chemistries for Magnesium Batteries: Challenges and Opportunities

“…[201] Despite a high degree of co-insertion (up to Li 1.27 Mg 1.27 Mo 6 S 8 ) observed in Mo 6 S 8 , Mg content in other co-inserted cathodes was still limited. [202,203] It seems that the intrinsic mobility of Mg is still decisive, which however might be improved if the assisting monovalent charge carrier was able to optimize the diffusion pathway such as coordination environment.…”