Zn₂GeO₄ and Zn₂SnO₄ nanowires for high-capacity lithium- and sodium-ion batteries

Abstract

Germanium (Ge) and tin (Sn) are considered to be the most promising alternatives to commercial carbon materials in lithium-and sodium-ion batteries. High-purity zinc germanium oxide (Zn2GeO4) and zinc tin oxide (Zn2SnO4) nanowires were synthesized using a hydrothermal method, and their electrochemical properties as anode materials in lithium-and sodium-ion batteries were comparatively investigated. The nanowires had a uniform morphology and consisted of singlecrystalline rhombohedral (Zn2GeO4) and cubic (Zn2SnO4) phases. For lithium ion batteries, Zn2GeO4 and Zn2SnO4 showed an excellent cycling performance, with a capacity of 1220 and 983 mA h g -1 after 100 cycles, respectively. Their high capacities are attributed to a combination of the alloy formation reaction of Zn and Ge (or Sn) with Li, and the conversion reaction: ZnO + 2Li + + 2e -↔ Zn + Li2O and GeO2 (or SnO2) + 4Li + + 4e -↔ Ge (or Sn) + 2Li2O. For the first time, we examined the cycling performance of Zn2GeO4 and Zn2SnO4 in sodium ion batteries; their capacities were 342 mA h g -1 and 306 mA h g -1 after 100 cycles, respectively. The capacity of Zn2SnO4 is much higher than the theoretical capacity (100 mA h g -1 ), while that of Zn2SnO4 is close to the theoretical capacity (320 mA h g -1 ). We suggest a contribution of the conversion reaction in increasing the capacities, which is similar to the case of lithium ion batteries. The present systematic comparison between the lithiation and sodiation will provide valuable information for the development of high-performance lithiumand sodium-ion batteries.

Zinc Ferrite Nanorod‐Assembled Mesoporous Microspheres as Advanced Anode Materials for Sodium‐Ion Batteries

“…With the cycle number increased to 300, the electrode still can deliver a high capacity of 350 mAh g −1 . The excellent cycling stability with high sodium storage capacity during the long‐life cycling test was superior to that reported previously for the ZnO and ZnM x O y (M = Co, Sn, Ge) electrodes for SIBs in Table . The rate property of the ZnFe 2 O 4 electrode at various current densities is shown in Figure c.…”

Electrochemical Performance of M2GeO4(M = Co, Fe and Ni) as Anode Materials with High Capacity for Lithium-Ion Batteries

“…The Co 2 GeO 4 electrode shows two reduction peaks at 0.78 and 0.37 V in the first cycle, which can be assigned to the disintegration of Co 2 GeO 4 crystal structure into its individual components such as Co, Ge, and the formation of Li 2 O, as given in equation (1) and the electrolyte decomposition [24,25]. The reduction peak at 0.02 V was associated with the alloying reaction of lithium with Ge to form the Li 4.4 Ge phase, as presented in equation 2 [26]. The small and broad oxidation peaks at 0.52 and 1.38 V during anodic scan could be attributed to the dealloying reaction of Li 4.4 Ge into Ge followed by the formation of GeO 2 [24].…”

A germanium and zinc chalcogenide as an anode for a high-capacity and long cycle life lithium battery

“…24,25 The introduction of another metal like Zn, which is also an electrochemically active species, can also accommodate the volume change during the charge/discharge process thus leading to long-term cycling stability. [26][27][28] Herein, we report on a germanium and zinc chalcogenide (GZC) and have investigated the electrochemical performance of the GZC electrode for the rst time. The GZC with its hierarchically porous structure and fast ion conductivity not only offers sufficient space to overcome the damage caused by the volume expansion of active materials during charge and discharge processes, but also provides highly efficient channels for the fast transport of lithium ions and abundant electrochemically active sites to achieve higher reversible capacity.…”