Defect Promoted Capacity and Durability of N-MnO Branch Arrays via Low-Temperature NH Treatment for Advanced Aqueous Zinc Ion Batteries.

Defect engineering (doping and vacancy) has emerged as a positive strategy to boost the intrinsic electrochemical reactivity and structural stability of MnO -based cathodes of rechargeable aqueous zinc ion batteries (RAZIBs). Currently, there is no report on the nonmetal element doped MnO cathode with concomitant oxygen vacancies, because of its low thermal stability with easy phase transformation from MnO to Mn O (≥300 °C). Herein, for the first time, novel N-doped MnO (N-MnO ) branch arrays with abundant oxygen vacancies fabricated by a facile low-temperature (200 °C) NH treatment technology are reported. Meanwhile, to further enhance the high-rate capability, highly conductive TiC/C nanorods are used as the core support for a N-MnO branch, forming high-quality N-MnO @TiC/C core/branch arrays. The introduced N dopants and oxygen vacancies in MnO are demonstrated by synchrotron radiation technology. By virtue of an integrated conductive framework, enhanced electron density, and increased surface capacitive contribution, the designed N-MnO @TiC/C arrays are endowed with faster reaction kinetics, higher capacity (285 mAh g at 0.2 A g ) and better long-term cycles (85.7% retention after 1000 cycles at 1 A g ) than other MnO -based counterparts (55.6%). The low-temperature defect engineering sheds light on construction of advanced cathodes for aqueous RAZIBs.