Departments of Materials and Chemistry, University of Oxford, Parks Road, Oxford, OX1 3PH, UK.
Angew Chem Int Ed Engl. 2017 Jun 1;56(23):6539-6543. doi: 10.1002/anie.201702432. Epub 2017 May 10.
Discharge in the lithium-O battery is known to occur either by a solution mechanism, which enables high capacity and rates, or a surface mechanism, which passivates the electrode surface and limits performance. The development of strategies to promote solution-phase discharge in stable electrolyte solutions is a central challenge for development of the lithium-O battery. Here we show that the introduction of the protic additive phenol to ethers can promote a solution-phase discharge mechanism. Phenol acts as a phase-transfer catalyst, dissolving the product Li O , avoiding electrode passivation and forming large particles of Li O product-vital requirements for high performance. As a result, we demonstrate capacities of over 9 mAh cm , which is a 35-fold increase in capacity compared to without phenol. We show that the critical requirement is the strength of the conjugate base such that an equilibrium exists between protonation of the base and protonation of Li O .
已知锂-O 电池的放电要么通过溶液机制发生，该机制能够实现高容量和高倍率，要么通过表面机制发生，该机制使电极表面钝化并限制性能。开发促进稳定电解质溶液中溶液相放电的策略是开发锂-O 电池的核心挑战。在这里，我们表明，在醚中引入质子给体苯酚可以促进溶液相放电机制。苯酚作为相转移催化剂，溶解产物 LiO，避免电极钝化并形成 LiO 产物的大颗粒 - 这是高性能的关键要求。结果，我们展示了超过 9 mAh cm 的容量，与没有苯酚相比，容量增加了 35 倍。我们表明，关键要求是共轭碱的强度，使得碱的质子化和 LiO 的质子化之间存在平衡。
