Reclaiming Reactive Oxygen Species With Taurine/Peroxytaurine Redox Couple for Achieving Ultra-Long-Term Cycle...

Li-rich Mn-based layered oxides (LRMOs) are essential cathode materials for higher energy densities in batteries. Nevertheless, the release of reactive oxygen species (ROS) at high voltages, accompanied by the migration of surface oxygen vacancies and transition metal ions, results in continuous electrolyte decomposition, irreversible phase transition, and nanovoids formation within bulk materials. These processes significantly shorten cycle life of batteries and limit practical applications. Herein, inspired by biological properties of taurine (TA) in scavenging ROS, we propose a straightforward cathode additive strategy by employing TA to effectively interact with ROS, thereby generating a reversible TA/peroxotaurine redox couple. This innovative mechanism enables efficient recycling of ROS, which in turn inhibits continuous electrolyte decomposition, O₂ release, and nanovoid formation. Furthermore, the derived high-quality cathode electrolyte interphase layer, which is rich in inorganic components and thinner in structure, stabilizes the layered structure while ensuring efficient Li⁺ transport kinetics. Consequently, the modified LRMO demonstrates an exceptional initial Coulombic efficiency of 89% (vs. 81% for LRMO), and a splendid capacity retention of 92% at 1C after 400 cycles (vs. 68% for LRMO). Additionally, the pouch cell paired with graphite anodes exhibits superior capacity retention of 78% after 1000 ultra-long cycles at 1/3C.