Choosing the right carbon additive is of vital importance for high-performance Sb-based Na-ion batteries

Abstract

OLC1300V as conductive carbon additive provides an optimum Sb–C interaction. A remarkable rate performance is attained, electrode cracking from volume expansion is prevented, and the solid electrolyte interphase homogeneity is significantly improved.

Interaction between Electrolytes and Sb2O3‐Based Electrodes in Sodium Batteries: Uncovering the Detrimental Effects of Diglyme

“…[10] If the surface layer is not flexible enough, it should crack due to volume expansion during the conversion reaction, which in turn leads to new side reactions on the exposed parts of the electrode. [16] This matches to the poor performance of the cell cycled in electrolyte solution E (Figure 2a) and to the results obtained in our previous work. [10] The electrode cycled in solution F (Figure 3d) is also covered by a surface layer.…”

“…[23,24,[26][27][28] Such effects substantially contribute to the stability of the electrolyte solution, which contains FEC towards the sodium electrodes, as was shown in a previous work. [16] Additionally, the Coulombic efficiency stabilizes at 98 % after 10 cycles, confirming a stabilization of the electrodes towards side reactions. Nevertheless, the processes are not entirely reversible, since, for rechargeable batteries, a Coulombic efficiency around 100 % for both anode and cathode in the cells is mandatory.…”

“…A further evaluation of the electrodes' surface chemistry in solution E is not implemented in the following course of this study, as the influence of parasitic reactions and decomposition products reasonably explains the poor electrochemical performance and these issues were already discussed elsewhere. [10,16]…”

“…Additionally, phase transitions can be partially irreversible and even if they are fully reversible, they may involve pronounced volume changes in each cycle, which leads to morphological instability, including massive detrimental electrode cracking. [12,15,16] Hu et al [17] reported promising features of Sb 2 O 3 as anode material for NIBs. High specific capacity, together with an exceptionally high rate performance and long cycling stability, were obtained due to the conversionalloy mechanism, which was clarified in their work.…”

“…[18][19][20] On the contrary to the results of Li et al [18] , Brehm et al [21] found that antimony shows very poor stability in the diglymebased electrolyte solutions when compared to other studies where alkyl carbonate-based electrolyte solutions were used. [16,22,23] The reason was not further evaluated, offering a basis for this work. There are conflicting opinions on whether diglyme brings advantages or not.…”