Understanding the lithiation/delithiation process in SnP2O7 anode material for lithium-ion batteries

SnP2O7 Covered Carbon Nanosheets as a Long‐Life and High‐Rate Anode Material for Sodium‐Ion Batteries

“…As shown in Figure a, all the diffractions could be indexed as those from cubic‐phase SnP 2 O 7 (joint committee on powder diffraction standards (JCPDS) Card, No. 29‐1352) composed by corner‐sharing SnO 6 octahedra and PO 4 tetrahedra linked together to form P 2 O 7 units (the inset of Figure b) . However, POP linkages in P 2 O 7 units are partially or completely bent at low temperature, resulting in a pseudo‐cubic structure with a tripled (3 × 3 × 3) unit cell.…”

Metal Ti quantum chain-inlaid 2D NaSn2(PO4)3/H-doped hard carbon hybrid electrodes with ultrahigh energy storage density

“…The higher charge-discharge voltage plateaus would promote its energy/power densities. Meanwhile, the overpotential between discharging/charging profiles is about 0.65 V, reflecting the good reaction kinetics [28]. Fig.…”

“…S14d). The CV curve of T 0.01 -QDs/2D-NSP/H-HC shows a discharge voltage plateau appears at 0.05 V and a charge voltage plateau appears at 0.51 V, which correspond to the alloying and dealloying process [28]. With an increasing scan rate, anodic potential shifts to higher voltages and the cathodic potential shifts to lower voltages, indicating an increased polarization at the higher sweep rates (Fig.…”

“…S9a, a pair of obvious redox peaks locates respectively at about 0.05 and 0.51 V, which correlates to the reversible redox reactions of NSP. An reduction peak at 1.03 V is observed at the first cycle and then disappears in the following cycles due to the formation of solid electrolyte interface (SEI) film on the anode surface [28]. The formation of SEI film causes an irreversible capacity loss of 39.6% in the first cycle (Fig.…”

“…Na super ionic conductor (NASICON)-type phosphates have also been widely investigated as anode materials for both Li-ion and Na-ion batteries because of their open framework structure and unique physical and chemical properties, such as, high ionic conductivity, mechanical stability, thermal stability [26]. Among them, Sn-based phosphates, such as SnP 2 O 7 [27,28], LiSn 2 (PO 4 ) 3 [29][30][31], NaSn 2 (PO 4 ) 3 [32][33][34] etc have been considered as a promising alternative to graphite as the anode materials owing to their natural abundance, recyclability, low working potential (less than 0.6 V vs. Li/Li + ), high theoretical capacity (993 mA h g -1 for Sn), more than twice of graphite (372 mAh g -1 ). However, the commercial application of those materials is limited by their low electrical conductivity and rapid capacity fading due to the large volume change during the charge-discharge process.…”