Magneli Ti₄O₇ nanotube arrays as a free-standing efficient interlayer for fast-delivery and high-energy density lithium-sulfur batteries

Improving lithium sulfur (Li-S) batteries performance has been a challenge due to sulfur drawbacks. Here, it addresses the use of Magneli Ti₄O₇ nano-tube arrays (MTNTAs) as free-standing interlayer in conjunction with carbon-coated separator (CCS) to improve the performance of lithium-sulfur batteries. The electrochemical catalytic activity of MTNTAs showed stable cycling and outstanding rate performance. The battery equipped with MTNTAs, and CCS delivered 723 mAh.g⁻¹ with a low capacity-fading rate of 0.07% per cycle at 0.5 C after 500 cycles. The remarkably fast Li ion diffusion and low internal resistance of MTNTAs provided a discharge capacity of 407 mAh.g⁻¹ after 500 cycles at 10 C. The high-sulfur loaded cathode (6.7 mg S. cm⁻²) can offer a discharge capacity of 719 mAh.g⁻¹ at 0.1 C corresponding to areal capacity of 4.8 mAh.cm⁻². The outperformance of the cell became drastically attractive when the cathode was fabricated with the simple blade-casting method using pure sulfur. The sulfur cathode delivered a superior discharge capacity of 471 mAh.g⁻¹ after 250 cycles with coulombic efficiency > 95% at 0.2 C. The result of this study demonstrates that the coexistence of MTNTAs and CCS in the battery can offer a long-life cycle with outstanding properties such as fast charging and discharging, and high-energy density which is highly desirable for transportation sectors. © 2023 Elsevier B.V.