The CGSe samples were synthesized according to the literature methods .
Na-ion storage properties of CGSe were evaluated using CR2032 coin-type half batteries.
The CGSe crystallizes in the cubic space group Im-3.
In open-framework CGSe, the 3D interconnected channels are constructed with the anionic selenide framework [[Cu.sub.8][Ge.sub.6][Se.sub.19]].sup.6-] and disordered charge-balanced species [([C.sub.5][H.sub.12]N).sup.+] [21, 24].
To explore the potential application of CGSe as SIB anode, we evaluated the electrochemical performances with the cyclic voltammetry (CV) and galvanostatic charge/discharge tests.
In the following two cycles, the almost-overlapped charge/discharge curves as well as the high CE indicate the good reversible properties of CGSe, which should result from the unique morphology and structure of open-framework CGSe.
In conclusion, the crystalline CGSe open-framework material was successfully prepared using a simple solvothermal method.
Caption: Figure 1: (a) XRD patterns and (b) HRTEM image of CGSe.
(b) View of the CGSe framework along the ab direction.