Prolonging the Cycle Life of a Lithium–Air Battery by Alleviating Electrolyte Degradation with a Ceramic–Carbon Composite Cathode

Abstract

Carbon materials with a high specific surface area are usually preferred to construct the air cathode of lithium–air batteries due to their abundant sites for oxygen reduction and discharge product growth. However, the high surface area also amplifies electrolyte degradation during charging, which would become the threshold of cyclability after addressing the issue of electrode passivation and pore clogging, but is usually overlooked in relevant research. Herein, it is proven that the critical influence of cathode surface area on electrolyte consumption by adopting carbon–ceramic composites to reduce the surface area of the air cathode. After screening several potential ceramic materials, an optimal composite of Ketjenblack (KB) and La0.7Sr0.3MnO3 (LSM) delivered a discharge capacity that was even higher than that of pure KB. This composite effectively mitigated the parasitic reaction current by 45 % if polarized at 4.4 V versus Li+/Li. Correspondingly, this composite prolonged the cycle life of the cell by 156 %. The results demonstrate that electrolyte consumption during charging is one of the critical boundary conditions to restrain the cyclic stability of lithium–air batteries.

Hybrid Ceramic-Gel Polymer Electrolyte with a 3D Cross-Linked Polymer Network for Lithium–Oxygen Batteries

“…Compared with the pristine electrode, the surface of the cathode after 5 cycles with LE is covered with a few clusters. In combination with the cycle performance, this may be attributed to the electrolyte decomposition caused by the attack of reduced oxygen species (O 2 – or Li 2 O 2 ), or the unstable SEI in the presence of oxygen. − Since certain precursor solution will penetrate into the pores on the shallow surface of the electrode and extend among the surface, the electrode morphologies of the SLFE-LAGP are quite different, with a significant increase in size. Overall, the surface of the SLFE-LAGP no longer exhibits the porous morphology of the pristine electrode but rather forms a unified morphology, which represents the integrated design of the electrolyte and porous cathode.…”

Tetramethylpyrazine: an electrolyte additive for high capacity and energy efficiency lithium–oxygen batteries

“…As mentioned above, TMP and Li + have a strong interaction, which will promote the solution growth mechanism of Li 2 O 2 , resulting in a higher discharge capacity. 28,32 Aer adding 100 mM TMP, it can be seen that the surface of the positive electrode is almost completely covered by the lm, and almost no spherical product is observed. Due to the passivation of the electrode by the insulating and insoluble products, the discharge performance of the cell would be affected.…”

“…30 The product obtained from surface mechanism is a thin lm adhered to the surface of the electrode which will passivate the cathode due to the insulation of Li 2 O 2 , resulting in low discharge capacity and poor cycle performance. 31,32 In contrast, solution mechanism can provide large-sized Li 2 O 2 with a higher discharge capacity. Therefore, promoting solution mechanism of Li 2 O 2 is the key to increase the actual discharge capacity.…”

Recent Advances in the Development of Li‐Air Batteries, Experimental and Predictive Approaches – Prospective, Challenges, and Opportunities

“…However, they also face several challenges and issues that have hindered their practical implementation. Some of the main problems faced by LABs include: Performance decay: Over time, the performance of LAB can degrade due to various factors, including electrode degradation, electrolyte decomposition, and accumulation of reaction products like lithium peroxide 94. This decay can result in reduced capacity, lower energy efficiency, and diminished overall performance. Sluggish kinetics for oxygen reduction/evolution: The oxygen reduction and evolution reactions, which involve the conversion of oxygen and lithium ions at the cathode, have slow kinetics.…”

“…Performance decay: Over time, the performance of LAB can degrade due to various factors, including electrode degradation, electrolyte decomposition, and accumulation of reaction products like lithium peroxide 94. This decay can result in reduced capacity, lower energy efficiency, and diminished overall performance.…”