N-Methyl-N-propyl pyrrolidine bromide (MPPBr) as a bi-functional redox mediator for rechargeable Li–O₂ batteries

Abstract

An ionic liquid, N-methyl-N-propyl pyrrolidine bromide (MPPBr), was introduced into the electrolyte of Li–O2 batteries as a bi-functional redox mediator (RM). It could effectively reduce the over-potential and facilitated the formation of a more stable SEI layer on the surface of Li foil.

Ru Single Atoms on N-Doped Carbon by Spatial Confinement and Ionic Substitution Strategies for High-Performance Li–O2 Batteries

“…One of the critical barriers that needs to be solved is the sluggish kinetics of the ORR and OER and complex electrochemistry processes of the real air−electrode reaction (a three-phase (oxygen/ electrode/electrolyte) interface reaction) as well as large discharge/charge overpotentials, which have a significant impact on the performance of LOBs. 12,13 In addition, generation of poor conductive Li 2 O 2 leads to electrical passivation of the cathode, blocking of the mass transfer and charge channels, and increase of the polarization resistance, thus hindering the further discharge reaction. 14,15 Consequently, it is vital to develop an effectively catalyzed cathode for the ORR and OER in LOBs.…”

“…On discharge, O 2 is reduced at the cathode (ORR), leading to formation of an intermediate superoxide lithium (LiO 2 ), which is then disproportionated or further reduced to lithium peroxide (Li 2 O 2 ). − On charge, Li 2 O 2 with the evolution (OER) is converted back to Li and O 2 . , In terms of the cathode, there are substantial obstacles to be overcome in order to meet the fundamental criteria for practical applications. One of the critical barriers that needs to be solved is the sluggish kinetics of the ORR and OER and complex electrochemistry processes of the real air–electrode reaction (a three-phase (oxygen/electrode/electrolyte) interface reaction) as well as large discharge/charge overpotentials, which have a significant impact on the performance of LOBs. , In addition, generation of poor conductive Li 2 O 2 leads to electrical passivation of the cathode, blocking of the mass transfer and charge channels, and increase of the polarization resistance, thus hindering the further discharge reaction. , Consequently, it is vital to develop an effectively catalyzed cathode for the ORR and OER in LOBs. On one hand, not only can LOBs cathode catalysts affect the discharge/charge potentials but also they determine the rechargeability of the cells as well as the Li 2 O 2 /cathode contact interface .…”

Free-Standing Carbon Nanofibers Protected by a Thin Metallic Iridium Layer for Extended Life-Cycle Li–Oxygen Batteries

“…To this end, we quantified the atomic percent of CO 3 2− in the CNFs and CNFs@Ir, not using the O−CO bonds to avoid confusion with signals coming from LiRCO 3 as well as from any other defects (or functional groups) in carbon. 38 atomic percentage of CO 3 2− on the CNFs was changed from 4.6 to 1.7% before and after the 5th cycle, indicating that 63% of Li 2 CO 3 could be removed upon charging. In contrast, up to 78% of Li 2 CO 3 could be removed from the Ir coating layers (4.54% → 1.0%).…”

“…To establish a correlation between the presence of the protective Ir layer and the amount of Li 2 CO 3 formed, we quantitatively calculated the atomic percentage of Li 2 CO 3 in the C 1 s spectra of the CNFs and CNFs@Ir, respectively (Figure f). To this end, we quantified the atomic percent of CO 3 2– in the CNFs and CNFs@Ir, not using the O–CO bonds to avoid confusion with signals coming from LiRCO 3 as well as from any other defects (or functional groups) in carbon. − The atomic percentage of CO 3 2– on the CNFs was changed from 4.6 to 1.7% before and after the 5th cycle, indicating that 63% of Li 2 CO 3 could be removed upon charging. In contrast, up to 78% of Li 2 CO 3 could be removed from the Ir coating layers (4.54% → 1.0%).…”

Synthesis and Characterization of Aero-Eutectic Graphite Obtained by Solidification and Its Application in Energy Storage: Cathodes for Lithium Oxygen Batteries

“…Probably, the charge potential used may have increased beyond 4.6 V, as reported in some previous works [35,38,39], assuming that the actual potential on the interface never reaches this value, and that the effect is attributed to an ohmic potential that increases it.…”