Practical implementation of next-generation Li-ion battery chemistries is to a large extent obstructed by the absence of an electrolyte that is capable of simultaneously supporting reversible electrochemical reactions at two extreme electrochemical potentials—above 4.5 V at the positive electrode and near 0 V vs. Li at the negative electrode. Electrolytes based on carbonate esters have been reliable in satisfying state-of-the-art Li-ion battery (LIB) chemistries below <4.2 V; however, it is the intrinsic thermodynamic tendency of these carbonates to decompose at potentials well below the thermodynamic threshold required for reversible reactions of high-voltage systems (>4.4 V), releasing CO₂. In this work, we explore a carbonate-free electrolyte system based on a single sulfone solvent, in which a newly discovered synergy between solvent and salt simultaneously addresses the interfacial requirements of both graphitic anode and high-voltage cathode (LiNi_0.5Mn_1.5O₄ (LNMO)). Experimental measurements, quantum chemistry (QC) calculations, and molecular dynamics simulations reveal the system’s fast ion conduction, stability over a wide temperature range, and non-flammability. At the anode, a LiF-rich interphase generated by early-onset reduction of the salt anion effectively suppresses solvent co-intercalation and subsequent graphite exfoliation, enabling unprecedented and highly reversible graphite cycling in a pure sulfone system. Under oxidative conditions, QC calculations predict that high salt concentration promotes complex/aggregate formation which slow the decomposition of sulfolane and leads to polymerizable rather than gaseous products—a fundamental improvement over carbonate solvents. These predictions are corroborated by X-ray photoelectron spectroscopy (XPS), cryogenic-transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS) experiments, which revealed the presence of a thin, conformal, sulfur-based cathode electrolyte interphase (CEI). Together, the functional interphases (SEI/CEI) generated by this electrolyte system supported long term operation of a high-voltage (4.85 V) LNMO/graphite full cell, which retained ∼70% of its original first-cycle discharge capacity after the 1000th cycle. Based on these results, this new carbonate-free electrolyte system, supported by the mechanistic understanding of its behavior, presents a promising new direction toward unlocking the potential of next generation Li-ion battery electrodes.

下一代锂离子电池化学方法的实际实施在很大程度上受到电解质的阻碍，该电解质能够在两个极端电化学势能下同时支持可逆电化学反应，这两个极端电化学势能为：正极4.5 V以上，接近0 V vs锂在负极。基于碳酸酯的电解质可以满足低于4.2 V的最新锂离子电池（LIB）化学要求；但是，这些碳酸盐的固有热力学趋势是在远低于高压系统可逆反应（> 4.4 V）所需的热力学阈值的电势下分解，释放出CO _2。。在这项工作中，我们探索了一种基于单一砜溶剂的无碳酸盐电解质系统，其中溶剂和盐之间的新发现的协同作用同时满足了石墨阳极和高压阴极（LiNi _0.5 Mn _1.5 O _4）的界面要求。（LNMO））。实验测量，量子化学（QC）计算和分子动力学模拟揭示了该系统的快速离子传导，在宽温度范围内的稳定性以及不燃性。在阳极处，通过早期还原盐阴离子而生成的富含LiF的界面有效地抑制了溶剂的共嵌入以及随后的石墨剥落，从而在纯砜系统中实现了空前的，高度可逆的石墨循环。在氧化条件下，QC计算表明，高盐浓度会促进络合物/聚集体的形成，从而减缓环丁砜的分解并导致可聚合而非气态产物的形成，这是对碳酸盐溶剂的根本改进。X射线光电子能谱（XPS）证实了这些预测，低温透射电子显微镜（TEM）和电子能量损失谱（EELS）实验，发现存在薄的，共形的硫基阴极电解质中间相（CEI）。该电解质系统产生的功能性相（SEI / CEI）共同支持了高压（4.85 V）LNMO /石墨全电池的长期运行，在第1000次放电后，该电池保留了约70％的原始第一循环放电容量循环。基于这些结果，这种新的无碳酸盐电解质系统在对其行为的机械理解的支持下，为释放下一代锂离子电池电极的电位提供了一个有希望的新方向。硫基阴极电解质相间（CEI）。该电解质系统产生的功能性相（SEI / CEI）共同支持了高压（4.85 V）LNMO /石墨全电池的长期运行，在第1000次放电后，该电池保留了约70％的原始第一循环放电容量循环。基于这些结果，这种新的无碳酸盐电解质系统在对其行为的机械理解的支持下，为释放下一代锂离子电池电极的电位提供了一个有希望的新方向。硫基阴极电解质相间（CEI）。该电解质系统产生的功能性相（SEI / CEI）共同支持了高压（4.85 V）LNMO /石墨全电池的长期运行，在第1000次放电后，该电池保留了约70％的原始第一循环放电容量循环。基于这些结果，这种新的无碳酸盐电解质系统在对其行为的机械理解的支持下，为释放下一代锂离子电池电极的电位提供了一个有希望的新方向。