Elevating the charge cut-off voltage beyond traditional 4.2 V is a commonly accepted technology to increase the energy density of Li-ion batteries (LIBs) but the risk of Li-dendrites and fire hazard increases as well. The use of ambi-functional additive, which forms stable solid electrolyte interphase (SEI) simultaneously at both cathode and anode, is a key to enabling a dendrites-free and well-working high-voltage LIB. Herein, a novel ambi-functional additive, pentaerythritol disulfate (PEDS), at 1 wt% without any other additive is demonstrated. We show the feasibility and high impacts of PEDS in forming lithium sulfate-incorporated robust SEI layers at NCM523 cathode and graphite anode in 1 Ah-level pouch cell under 4.4 V, 25 °C and 0.1 C rate, which mitigates the high-voltage instability, metal-dissolution and cracks on NCM523 particles, and prevents Li-dendrites at graphite anode. Improved capacity retention of 83% after 300 cycles is thereby achieved, with respect to 69% with base electrolyte, offering a promising path toward the design of practical high-energy LIBs.

将充电截止电压提高到超过传统的 4.2 V 是提高锂离子电池 (LIB) 能量密度的普遍接受的技术，但锂枝晶和火灾危险的风险也会增加。双功能添加剂的使用在正极和负极同时形成稳定的固体电解质界面 (SEI)，是实现无枝晶且工作良好的高压 LIB 的关键。在此，展示了一种新型双功能添加剂季戊四醇二硫酸盐 (PEDS)，浓度为 1 wt%，不含任何其他添加剂。我们展示了 PEDS 在 4.4 V、25 °C 和 0.1 C 倍率下在 1 Ah 级软包电池的 NCM523 阴极和石墨阳极形成结合硫酸锂的坚固 SEI 层的可行性和高影响，这减轻了高压不稳定性, NCM523 颗粒上的金属溶解和裂纹, 并防止石墨负极处的锂枝晶。因此，在 300 次循环后，容量保持率提高了 83%，而基础电解质为 69%，为设计实用的高能 LIB 提供了一条有希望的途径。