Dictating High‐Capacity Lithium–Sulfur Batteries through Redox‐Mediated Lithium Sulfide Growth,Small Methods

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Dictating High‐Capacity Lithium–Sulfur Batteries through Redox‐Mediated Lithium Sulfide Growth
Small Methods ( IF 10.7 ) Pub Date : 2019-06-07 , DOI: 10.1002/smtd.201900344
Meng Zhao _{1,

2} , Hong‐Jie Peng ₃ , Jun‐Yu Wei _{1,

2} , Jia‐Qi Huang _{1,

2} , Bo‐Quan Li ₃ , Hong Yuan ₃ , Qiang Zhang ₃

Affiliation

Regulating the solid product growth is critical for achieving high capacities in rechargeable batteries based upon multiphase and multielectron dissolution–precipitation chemistries (e.g., lithium–sulfur chemistry). The intrinsic redox mediators, polysulfides, are insufficient for effective regulation due to the dynamically changed species and concentration. Herein cobaltocene (CoCp₂) is introduced as a persistent extrinsic redox mediator to dictate an alternative growing pathway toward three‐dimensional lithium sulfide growth, which enables at most 8.1 times enhancement in discharge capacities at harsh conditions of high‐rate (>1 C) or electrolyte‐lean operation (electrolyte/sulfur ratio of 4.7 µL mg_S⁻¹). The faster kinetics and higher diffusivity of CoCp₂ play an essential role in regulating lithium sulfide growth and increasing discharge capacities. This work not only illustrates an effective strategy to increase the capacity of high‐rate or electrolyte‐lean lithium–sulfur batteries but also paves a way toward the rational design of novel redox mediators for dissolution–precipitation energy chemistries.

中文翻译：

通过氧化还原介导的硫化锂生长来定向大容量锂硫电池

调节固体产品的生长对于基于多相和多电子溶解-沉淀化学方法（例如，锂-硫化学方法）的可再充电电池实现高容量至关重要。由于种类和浓度的动态变化，内在的氧化还原介体多硫化物不足以进行有效调节。此处引入钴（CoCp ₂）作为持久的外在氧化还原介体，以指示通往三维硫化锂生长的替代生长途径，该途径可在高速率（> 1 C）的苛刻条件下将放电容量提高至多8.1倍或贫电解液运行（电解液/硫比为4.7 µL mg _S^-1）。CoCp ₂更快的动力学和更高的扩散率在调节硫化锂的生长和增加放电容量方面起着至关重要的作用。这项工作不仅说明了提高高倍率或贫电解质锂-硫电池容量的有效策略，而且还为合理设计用于溶解-沉淀能化学的新型氧化还原介体铺平了道路。

更新日期：2019-06-07

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