Balland Véronique, Mateos Mickaël, Singh Arvinder, Harris Kenneth D, Laberty-Robert Christel, Limoges Benoît
Université de Paris, Laboratoire d'Electrochimie Moléculaire, UMR CNRS 7591, Paris, F-75013, France.
Laboratoire de Chimie de la Matière Condensée de Paris, Sorbonne Université, Paris, F-75005, France.
Small. 2021 Jun;17(23):e2101515. doi: 10.1002/smll.202101515. Epub 2021 May 6.
Rechargeable aqueous aluminium batteries are the subject of growing interest, however, the charge storage mechanisms at manganese oxide-based cathodes remain poorly understood. In essense, every study proposes a different mechanism. Here, an in situ spectroelectrochemical methodology is used to unambiguously demonstrate that reversible proton-coupled MnO -to-Mn conversion is the main charge storage mechanism occurring at MnO cathodes for a range of slightly acidic Al -based aqueous electrolytes, with the Al hexaaquo complex playing the key role of proton donor. In Zn/MnO assemblies, this mechanism is associated with high gravimetric capacities and discharge potentials, up to 560 mAh g and 1.65 V respectively, attractive efficiencies (CE > 99.5% and EE > 82%) and excellent cyclability (almost 100% capacity retention over 1 400 cycles at 2 A g ). Finally, a critical analysis of the data previously published on MnO cathodes in Al -based aqueous electrolytes is conducted to conclude on a universal charge storage mechanism, i.e., the reversible electrodissolution/electrodeposition of MnO .
可充电水系铝电池越来越受到关注，然而，基于氧化锰的阴极的电荷存储机制仍未得到充分理解。实际上，每项研究都提出了不同的机制。在此，采用原位光谱电化学方法明确证明，对于一系列微酸性铝基水系电解质，可逆质子耦合MnO到Mn的转化是MnO阴极发生的主要电荷存储机制，其中铝六水络合物起到质子供体的关键作用。在锌/氧化锰组件中，这种机制具有高比容量和放电电位，分别高达560 mAh g和1.65 V，具有吸引力的效率（库仑效率> 99.5%，能量效率> 82%）和出色的循环稳定性（在2 A g下1400次循环中容量保持率几乎为100%）。最后，对先前发表的关于铝基水系电解质中MnO阴极的数据进行了批判性分析，以得出一种通用的电荷存储机制，即MnO的可逆电溶解/电沉积。
