Department of Chemistry-Ångström Laboratory, Uppsala University, Box 538, SE-75121 Uppsala, Sweden.
Dalton Trans. 2018 Aug 7;47(31):10752-10758. doi: 10.1039/c8dt01068d.
Tin phosphide (Sn4P3) is here investigated as an anode material in half-cell, symmetrical, and full-cell sodium-ion batteries. Results from the half-cells using two different electrolyte salts of sodium bis(fluorosulfonyl)imide (NaFSI) or sodium hexafluorophosphate (NaPF6) show that NaFSI provides improved capacity retention but results from symmetrical cells disclose no advantage for either salt. The impact of high and low desodiation cut-off potentials is studied and the results show a drastic increase in capacity retention when using the desodiation cut-off potential of 1.2 V as compared to 2.5 V. This effect is clear for both NaFSI and NaPF6 salts in a 1 : 1 binary mixture of ethylene carbonate and diethylene carbonate with 10 vol% fluoroethylene carbonate. Hard X-ray photoelectron spectroscopy (HAXPES) results revealed that the thickness of the solid electrolyte interphase (SEI) changed during cycling and that SEI was stripped from tin particles when tin phosphide was charged to 2.5 V with NaPF6 based electrolyte.
磷化锡（Sn4P3）在此被用作半电池、对称电池和全电池钠离子电池的阳极材料进行研究。使用两种不同的电解质盐——双（氟磺酰）亚胺钠（NaFSI）或六氟磷酸钠（NaPF6）的半电池结果表明，NaFSI 提供了更好的容量保持率，但对称电池的结果表明两种盐都没有优势。研究了高脱钠截止电位和低脱钠截止电位的影响，结果表明与 2.5 V 相比，使用 1.2 V 的脱钠截止电位时，容量保持率会急剧增加。在碳酸乙烯酯和碳酸二乙酯的 1∶1 二元混合物中加入 10 vol%氟代碳酸乙烯酯，NaFSI 和 NaPF6 盐均表现出这种效果。硬 X 射线光电子能谱（HAXPES）结果表明，在循环过程中固体电解质界面（SEI）的厚度发生了变化，并且当使用基于 NaPF6 的电解质将磷化锡充电至 2.5 V 时，SEI 从锡颗粒上剥落。
