Unraveling the New Role of Manganese in Nano and Microstructural Engineering of Ni-Rich Layered Cathode for Advanced Lithium-Ion Batteries

Abstract

Substantial endeavors are dedicated to advance the electrochemical performance of Ni-rich Li[Ni1−x−yCoxMny]O2 (NCM) and Li[Ni1−x−yCoxAly]O2 (NCA) cathode, with a particular focus on doping, aimed at addressing cycling durability and thermal stability of the cathodes. Mn is widely considered an attractive dopant because of its abundance and considerably lower cost than other dopant candidates. However, despite the long history of research, the role of Mn doping remains poorly understood, confined to the historical level, and associated with crystal structural and chemical aspects. Herein, the role of Mn doping beyond its classical role is redefined, particularly in terms of cathode microstructure. Introducing excess Mn during calcination significantly engineers the nano- and micro-level structural features of the peripheral grains of the Li[Ni0.910Co0.079Al0.011]O2 cathode. The microstructural modification achieved by doping with 4 mol% Mn significantly improves the electrochemical cycling performance of the cathode, extending the capacity retention up to 76.5% after 1000 cycles under fast charging conditions (3 C and 45 °C). Hence, by providing an alternative approach to redesign the structural features of the cathode, Mn doping offers a significant step toward the sustainable development of high-performance Ni-rich Li[Ni1−x−y−zCoxMnyAlz]O2 (NCMA) cathodes for next-generation lithium-ion batteries.