High-Rate Long Cycle-Life Li-Air Battery Aided by Bifunctional InX₃ (X = I and Br) Redox Mediators

Abstract

Redox mediators (RMs) are solution-based additives that have been extensively used to reduce the charge potential and increase the energy efficiency of Li–oxygen (Li–O2) batteries. However, in the presence of RMs, achieving a long cycle-life operation of Li–O2 batteries at a high current rate is still a major challenge. In this study, we discover a novel synergy among InX3 (X = I and Br) bifunctional RMs, molybdenum disulfide (MoS2) nanoflakes as the air electrode, dimethyl sulfoxide/ionic liquid hybrid electrolyte, and LiTFSI as a salt to achieve long cycle-life operations of Li–O2 batteries in a dry air environment at high charge–discharge rates. Our results indicate that batteries with InI3 operate up to 450 cycles with a current density of 0.5 A g–1 and 217 cycles with a current density of 1 A g–1 at a fixed capacity of 1 A h g–1. Batteries with InBr3 operate up to 600 cycles with a current density of 1 A g–1. These batteries can also operate at a higher charge rate of 2 A g–1 up to 200 cycles (for InBr3) and 160 cycles (for InI3). Our experimental and computational results reveal that while X3 – is the source of the redox mediator, LiX at the MoS2 cathode, In3+ reacts on the lithium anode side to form a protective layer on the surface, thus acting as an effective bifunctional RM in a dry air environment. This evidence for a simultaneous improvement in the current rates and cycle life of a battery in a dry air atmosphere opens a new direction for research for advanced energy storage systems.

Tuning aprotic solvent properties with long alkyl chain ionic liquid for lithium-based electrolytes

“…However, the authors emphasized the challenge of detecting the redox peak (Br 3 À /Br 2 ) due to the DMSO voltage window. 50 In the present paper, we observed that the decomposition of DMSO began near to 4.20 V, as can be visualized in the inset of Fig. 2.…”

“…By performing cyclic voltammetry it is possible to understand the electrochemical behavior of an electrolyte in the battery operational voltage range. The electrochemical behavior provides information related to the redox properties of the electrolyte, 49,50 which helps to distinguish the electrolyte applicability in different types of electrochemical devices. In the case of lithium-based batteries, a wide electrochemical stability means that the cell can operate for multiple cycles without signicant changes in the potential prole, which prevents the electrolyte degradation and improves the battery cycle life, and is fundamental to produce commercial prototypes.…”

Light‐Assisted Li–O2 Batteries with Lowered Bias Voltages by Redox Mediators

“…[ 6 ] Another well‐accepted strategy is the proper introduction of soluble redox mediators, [ 7 ] such as LiI, 2,2,6,6‐Tetramethylpiperidinooxy (TEMPO) and tetrathiafulvalene (TTF). [ 8 ] Despite the shuttle effect and inherent instability involved, it is undeniable that this strategy is effective in catalyzing the OER or ORR process and realizing the cycle of insoluble and insulating Li 2 O 2 . [ 9 ]…”

Novel Co‐Catalytic Activities of Solid and Liquid Phase Catalysts in High‐Rate Li‐Air Batteries

“…Third, it is not clear where or what the active sites are for O 2 reduction on the SnS surface and DFT calculations are used to provide insight into this aspect of the discharge mechanism, which has implications for the improved performance over the previously studied MoS 2 catalyst, as one of the best catalysts for Li‐air battery system. [ 18,32,46,72,73 ]…”