Search

Sodium ion batteries based on the more sodium source reserve than that of lithium have been designed as promising alternatives to lithium ion batteries. However, several problems including unsatisfied specific capacity and serious cyclic stability must be solved before the reality. One of the effective approaches to solve the abovementioned problems is to search for suitable anode materials. In this work, we designed and prepared FeSe2 nanoflakes via a simple hydrothermal method which can be adjusted in composition by Fe precursor. As a potential anode for sodium storage, the optimized FeSe2 electrode was further evaluated in different electrolytes of NaClO4 in propylene carbonate/fluoroethylene carbonate and NaCF3SO3 in diethylene glycol dimethyl ether. The capacity was about 470 mAh g − 1 and 535 mAh g − 1 at 0.5 A g − 1 , respectively, in the voltage between 0.5 V and 2.9 V in the cycle of stabilization phase. Superior performance both in capacity and in stability was obtained in ether-based electrolyte, which affords the property without plugging the intermediates of transition metal dichalcogenides during charge/discharge processes. FeSe2 nanoflakes with high sodium storage capacity were prepared by one-step hydrothermal reaction. As a result, the optimized FeSe2 electrode exhibited a high reversible capacity of 535 mAh g–1 after 500 cycles at 500 mA g–1. The comparison of the performance in different electrolytes indicated that ether-based electrolytes could avoid the reaction with the anionic group of the charge/discharge products, leading to the superior stability. [ABSTRACT FROM AUTHOR]