Neutron diffraction probing hydrogen in monoclinic H2VOPO4

Unraveling the Multielectron Redox Reactions of β-VOPO4 for Sodium Ion Batteries

“…Similar trends have also been reported in various VOPO 4 -based polymorphs (Figure S12 and Table S7). ,, The average V–O bond length of the o-NaVOPO 4 phase is 1.98 Å, which is similar to the one measured for the β-Na 0.93 VOPO 4 phase by the joint X-ray and neutron diffraction analysis and is consistent with the +4 oxidation state of the V ion. The average V–O bond length increases to 2.06 Å for o-Na 2 VOPO 4 , which should contain only V 3+ based on the chemical formula.…”

“…The average V–O bond length increases to 2.06 Å for o-Na 2 VOPO 4 , which should contain only V 3+ based on the chemical formula. In comparison, the experimental V­(III)–O bond length reported for ε-Li 2 VOPO 4 and H 2 VOPO 4 is 2.02–2.03 Å. , …”

“…In comparison, the experimental V(III)−O bond length reported for ε-Li 2 VOPO 4 and H 2 VOPO 4 is 2.02− 2.03 Å. 34,35 The distortion of the VO 6 octahedra is characterized by the standard deviation of the bond lengths, which is shown as the error bar in Figure 13B. The bond length variation for the o-NaVOPO 4 phase is similar to the β-Na 0.93 VOPO 4 phase, which is mainly caused by the formation of the short vanadyl bond for V 4+ species.…”