• • HTS-S achieved a discharge capacity of 144.05 mAh g−1 within 2.0–4.1 V, with charge capacities of 145.33 mAh g−1 and discharge capacity of 150.71 mAh g−1 in specific tests, demonstrating superior capacity retention and rate capability compared to HTS-D and HTS-O, which is critical for meeting the energy density demands of commercial SIBs in grid storage and electric vehicles.
• • The pre-reacted precursor enabled the synthesis of impurity-free O3-NaCu0.2Fe0.3Mn0.5O2, eliminating phase impurities that degrade cycling stability; this purity directly translates to enhanced structural integrity and longer cycle life, addressing a key bottleneck in layered oxide cathodes.
• • At a cutting voltage of 4.1 V, HTS-S exhibited enhanced Na extraction during charging, leading to improved charge capacity and suppressed polarization compared to HTS-D, which is essential for high-power applications requiring fast charging and high round-trip efficiency.
• • Increased Mn participation in charge compensation below 2.25 V contributed to enhanced specific capacity, leveraging the redox activity of manganese to boost energy density without compromising cost, as manganese is earth-abundant and inexpensive.