Na-Ion storage in iron hydroxide phosphate hydrate through a reversible crystalline-to-amorphous phase transition

Abstract

Iron(iii) hydroxide phosphate hydrate Fe1.13(PO4)(OH)0.39(H2O)0.61 is investigated for the first time as a Na-ion battery cathode. The material exhibits similar storage capacities for Na- and Li-ions at relatively low current rates (i.e. C/10).

Expanded solid-solution behavior and charge-discharge asymmetry in NaxCrO2 Na-ion battery electrodes

“…For the battery cell employing liquid electrolyte (LE-cell), an electrode composite was prepared from conductive carbon, active material (NaCrO 2 ), and binder in a mass ratio of 2:6:2 as described in previous work [31][32][33][34]. Conductive carbon and binder (Graphite C-Nergy SFG6L, 99.5%, Imerys Graphite and Carbon, acetylene black VXC72, Cabot Corporation, and Kynar PVDF Arkena Inc.) were pre-dried at 60 • C in a vacuum oven for >4 h before being imported into the glove box [30].…”

Understanding disorder in oxide-based electrode materials for rechargeable batteries

“…A reversible order-disorder transition has also recently been reported for Lipscombite Fe 2−y (PO 4 )(OH) 3−3y (H 2 O) 3y−2 [90]. As Na-ions are inserted into the material, a Na x Fe 2−y (PO 4 ) (OH) 3−3y (H 2 O) 3y−2 solid solution forms, however as xNa increases, the crystalline solid solution transforms into an amorphous phase (figure 5).…”

“…the Na-poor NaxFe 2−y (PO4)(OH) 3−3y (H2O) 3y−2 .Notice the low Bragg intensity at the end of discharge (as main fraction of the material is amorphous at this point), and that the Bragg intensity is regained upon recharge. Reproduced from[90] with permission of The Royal Society of Chemistry.…”