On the influence of particle morphology to provide high performing chemically desodiated C@NaV2(PO4)3 as cathode for rechargeable magnesium batteries

Reversible Electrochemical Insertion/Extraction of Magnesium Ion into/from Robust NASICON-Type Crystal Lattice in a Mg(BF4)2-Based Electrolyte

“…Notably, the well-defined charge and discharge plateaus were reversibly obtained as shown in Figure b. Although the cycle performance in Figure c shows moderate capacity fading resulting in 87 mAh g –1 in the 20th cycle, the cyclability is believed to be ameliorated by modifying NVP crystals and improving the synthetic process of composite electrodes. , It should be highlighted that, as the discharge plateau potential of −0.3 V (vs Ag + /Ag) is comparable to 2.7 V (vs Mg 2+ /Mg), the galvanostatic measurement result unveils that the desodiated NVP cathode affords >2.5 V-class secondary MBs if assembled with a Mg metal anode and an ideal electrolyte.…”

“…The subsequent anodic scan gave rise to a relatively sharp oxidative signal with the peak at 0.2 V (vs Ag + /Ag) accompanied by a small shoulder band at −0.1 V (vs Ag + /Ag). The pair of redox signals was found to be reversible, which can be attributed to the V 3+ /V 4+ redox reaction associated with Mg 2+ insertion/extraction into/from the NASICON-type host lattice, − while the bandwidth gradually broadened on cycling. The broadening indicates an increase of resistivity possibly associated with the compromised crystallinity as discussed later.…”

“…Recently, the electrochemical behaviors for the charged state of NVP electrodes (desodiated NVP) in the Mg salt-based electrolytes have been reported, which verified the successful Mg 2+ insertion into the empty sites in the desodiated NVP. − However, details about this electrochemical reaction still remain ambiguous because of the unreliable cell setup in these studies. Electrochemical measurements using a two-electrode cell (coin-type cell) gives no information on the redox potential of a working electrode.…”

Enhancing Na+ Extraction Limit through High Voltage Activation of the NASICON-Type Na4MnV(PO4)3 Cathode

“…Further charge from 3.8 to 4.0 V is accompanied by extraction of Na + mainly from the Na1 position; its occupancy decreases to 0.87(1). In contrast to Na 3 V 2 (PO 4 ) 3 , , Na 4 MnV­(PO 4 ) 3 , and desodiated NaV 2 (PO 4 ) 3 , at this state of charge the average Na1–O distance is longer than the average Na2–O distance (Table S2), which can be related to the “unlocking” of the Na1 site. Total Na content in the electrode charged to 4.0 V, as determined from Rietveld refinement, is 1.77, which is in a good agreement with the electrochemical data.…”

Exploits, advances and challenges benefiting beyond Li-ion battery technologies

“…The layered TiS 2 /TiS 3 /TiSe 2 [122][123][124], V 2 O 5 [110,[125][126][127] and MoO 3 [126] have been explored demonstrating low to moderate capacities and reversibility. In search for higher capacities, faster intercalation kinetics, and lower migration barriers for Mg 2+ , nanosizing, doping (for example, with H 2 O, F) and creating defects, and forming solid solutions have been undertaken with variable outcomes [128][129][130][131].…”