Simple synthesis and electrochemical performance of NaVSi ₂ O ₆ as a new sodium‐ion cathode material

Abstract

Summary Developing new sodium‐ion battery (SIB) cathode materials with low cost and high capacity remains a challenge. Here, NaVSi2O6 was successfully synthesized by a simple sol‐gel method for the first time. This material was used as a new SIB cathode material. At a current density of 20 mA g−1, the first discharge specific capacity is 80 mA h g−1, which exhibits a higher capacity. The mechanism of the cycle stability of NaVSi2O6 was elucidated by the theoretical calculations. The volume and formation energy change of different content of Na+ insertion/extraction, as well as the energy band and density of states were calculated combined with the density functional theory (DFT). Our research results provide a reference for further exploring the NaMSi2O6 (M = Fe, Cr, and V) compounds as cathode materials of SIB.

Application of First Principles Computations Based on Density Functional Theory (DFT) in Cathode Materials of Sodium-Ion Batteries

“…For the first time, Wei et al [69] synthesized NaVSi 2 O 6 cathode material by the simple sol-gel method. Combined with DFT, they calculated the formation energy changes of Na + insertion with different contents and determined the structural changes of the material during charging and discharging by using the volume changes.…”

Intrinsic Defects, Diffusion and Dopants in AVSi2O6 (A = Li and Na) Electrode Materials

“…Interest in AVSi 2 O 6 (A = Li and Na) materials as cathodes for the application of rechargeable batteries has emerged in recent years due to the existence of variable oxidation states of vanadium, leading to redox reactions [34][35][36]. Li 2 VSi 2 O 6 was reported to be a potential cathode material for use in Li-ion batteries [34,35].…”

“…Two different high capacities of 85 mAhg -1 and 181 mAhg -1 were measured at 30 • C and 60 • C, respectively, due to the introduction of additional 0.42 Li + ions arising from redox reactions (V 3+ /V 4+ and V 2+ /V 3+ ) [34]. Very recently, a sol-gel method was used to prepare a high-capacity NaVSi 2 O 6 cathode material yielding a specific capacity of 80 mAhg -1 [36]. Density functional theory simulation was used to examine the stability of Na insertion into NaVSi 2 O 6 , and it was concluded that poor cycle stability is directly related to the significant volume change [36].…”

“…Very recently, a sol-gel method was used to prepare a high-capacity NaVSi 2 O 6 cathode material yielding a specific capacity of 80 mAhg -1 [36]. Density functional theory simulation was used to examine the stability of Na insertion into NaVSi 2 O 6 , and it was concluded that poor cycle stability is directly related to the significant volume change [36]. Although a number of experimental studies have investigated the performance of AVSi 2 O 6 (A = Li and Na), theoretical studies of the defects and ion transport rates are lacking in the literature.…”