Although lithium sulfur batteries made a lot of progress over decades, they are still faced with low energy and fragile stability. Herein, we report a new strategy to achieve extremely high energy lithium sulfur battery with dimethyl polysulfide intermediates, which can greatly increase the specific capacity to 1497.3 mAh g^–1 at 0.1C, and dendrite–free lithium anode so as to ensure a long lifespan with 500 cycles. The brilliant performance is attributed to the radical exchange between sulfur and dimethyl polysulfide intermediates rather than lithium polysufides. Density functional theory calculations and nuclear magnetic resonance spectroscopy verify the existence of dimethyl polysulfide intermediates and in–situ UV/Vis spectroscopy confirms that mechanism for exchange reaction of radicals can boost the capacity of sulfur cathodes by eliminating complications, such as shuttle effect associated with formation and transformation of lithium polysulfides in the electrolyte. This study develops a new avenue for the innovative discharge intermediate design that helps increase capacity and stability for the practical application of lithium sulfur batteries.

尽管锂硫电池在几十年中取得了长足的进步，但它们仍然面临着低能耗和脆弱的稳定性。在此，我们报告了一种新战略，该战略将通过使用二甲基聚硫醚中间体实现极高能量的锂硫电池，该方法可在0.1C时将比容量大大提高至1497.3 mAh g ^–1，并使用无枝晶的锂阳极以确保长寿命500个周期。出色的性能归因于硫和二甲基多硫化物中间体之间的自由基交换，而不是多硫化锂。密度泛函理论计算和核磁共振波谱验证了二甲基多硫化物中间体的存在和原位UV / Vis光谱证实，自由基的交换反应机理可以通过消除复杂性（例如与电解质中多硫化锂的形成和转变相关的穿梭效应）来提高硫阴极的容量。这项研究为创新的放电中间设计开辟了一条新途径，有助于为锂硫电池的实际应用增加容量和稳定性。