The sulfate esters of 1,3,2-dioxathiolane 2,2-dioxide (DTD) and trimethylene sulfate (TMS) are evaluated as electrolyte additives for K-metal cells. A symmetric K∥K cell filled with 0.8 M KPF₆/EC:DEC + 1 wt % of DTD electrolyte delivers plating–stripping polarization of ∼20 mV, i.e., ∼10 mV per K electrode, which is significantly lower than those for the additive-free and TMS-added electrolyte cells. Moreover, a K∥K₂Mn[Fe(CN)₆] cell filled with the DTD-added electrolyte exhibits a larger reversible capacity and suppressed irreversible capacity than the DTD-free cells. Electrochemical tests and gas chromatography–mass spectrometry (GC–MS) reveal that DTD addition is efficient in passivating the K-metal surface and inhibiting the formation of electrolyte-soluble oligocarbonates, which are formed in the DTD-free electrolyte. The oligocarbonates are oxidized on the positive electrode and cause irreversible capacity. Thus, the DTD additive enables the high reversibility and low polarization of K-metal cells.

中文翻译：

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1,3,2-二氧杂硫杂环戊烷 2,2-二氧化物作为钾金属电池的电解质添加剂

1,3,2-二氧杂硫杂环戊烷 2,2-二氧化物 (DTD) 和三亚甲基硫酸盐 (TMS) 的硫酸酯被评估为 K 金属电池的电解质添加剂。对称 K∥K 电池填充 0.8 M KPF ₆ /EC:DEC + 1 wt % DTD 电解液可提供 ~20 mV 的电镀剥离极化，即每 K 电极 ~10 mV，这明显低于无添加剂和添加 TMS 的电解质电池。此外，K∥K ₂ Mn[Fe(CN) ₆] 填充了添加 DTD 的电解质的电池比不含 DTD 的电池表现出更大的可逆容量和抑制的不可逆容量。电化学测试和气相色谱-质谱法 (GC-MS) 表明，添加 DTD 可有效钝化 K 金属表面并抑制在不含 DTD 的电解质中形成的可溶于电解质的低聚碳酸酯的形成。低聚碳酸酯在正极上被氧化并导致不可逆容量。因此，DTD 添加剂能够实现 K 金属电池的高可逆性和低极化。