Manganese alchemy: Atomic-scale doping to miniaturize cobalt oxide in nanofiber architecture for ultra-fast lithium-ion batteries

Lithium-ion batteries (LIBs) are essential for modern portable electronics and future mobility solutions, yet improving fast-charging capabilities and cycling stability remains a considerable challenge. This study investigates a new strategy to enhance LIB anode performance by incorporating manganese (Mn)-doped (0, 0.05, 0.1, and 0.2 at.%) cobalt oxide (Co 3 O 4 ) nanofibers. Mn doping facilitates the downsizing of Co 3 O 4 nanograins interconnected along the one-dimensional nanofibers by inducing lattice distortions and creating oxygen vacancies, which improve electronic conductivity and reactivity. The integration of Mn dopants into the Co 3 O 4 host reduces grain size, shortens Li + diffusion pathways, and increases the Li-ion accessible area, thereby enhancing electron/Li + transport and cycling stability. The LIB cell with the optimized Mn doping level (0.2 at.%) achieves minimized side reactions, a high specific capacity of 1237 mAh g −1 at 500 mA g −1 after 300 cycles, and an impressive capacity of 490 mAh g −1 even at an extremely high current density of 5 A g −1 . This study advances LIB anode design through tailored doping engineering to control grain size, achieving desired structural and electrochemical properties and providing valuable insights for sustainable energy technologies. • Mn-doped (0–0.2 at.%) Co 3 O 4 nanofibers enhance LiB anode performance. • Atomic Mn-doping reduces Co 3 O 4 size, improving lithium storage kinetics. • Mn doping creates oxygen vacancies, boosts conductivity, and enhances stability. • Optimized 0.2 at.% Mn doping minimizes side reactions and improves high-rate capacity.