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Spinel LiNi0.5Mn1.5O4 (LNMO) is a promising cathode candidate for the next‐generation high energy‐density lithium‐ion batteries (LIBs). Unfortunately, the application of LNMO is hindered by its poor cycle stability. Now, site‐selectively doped LNMO electrode is prepared with exceptional durability. In this work, Mg is selectively doped onto both tetrahedral (8a) and octahedral (16c) sites in the Fd3‾ m structure. This site‐selective doping not only suppresses unfavorable two‐phase reactions and stabilizes the LNMO structure against structural deformation, but also mitigates the dissolution of Mn during cycling. Mg‐doped LNMOs exhibit extraordinarily stable electrochemical performance in both half‐cells and prototype full‐batteries with novel TiNb2O7 counter‐electrodes. This work pioneers an atomic‐doping engineering strategy for electrode materials that could be extended to other energy materials to create high‐performance devices. [ABSTRACT FROM AUTHOR]

Core-shell Mn 3 O 4 /carbon (Mn 3 O 4 @C) hybrid fiber are synthesized by encapsulating Mn 3 O 4 nanoparticles (NPs) in the hollow carbon fibers (Mn 3 O 4 @HCFs) according to the coaxial electrospinning technique. As the aqueous Zinc ion battery (ZIBs) cathode, the well-defined Mn 3 O 4 @HCFs with 12.7 wt % carbon exhibits superior rate capability (215.8 and 115.7 mAh g−1 at 0.3 and 2.0 A g−1, respectively) and excellent cycling stability (225 mAh g−1 remaining at the current density of 400 mA g−1 after 1300 cycles). The outstanding electrochemical performances are attributed to the core-shell structure of the Mn 3 O 4 @HCFs with much void spaces. The carbon framework on the surface of the Mn 3 O 4 NPs can not only relieve the volume expansion of Mn 3 O 4 during the discharging, but also optimize the electron transportation inside these fibers for the electrode. Furthermore, the amorphous carbon shell could also reduce the dissolution of the Mn 3 O 4 NPs during cycling. This work will provide a new pathway of a technique for enhancing the manganese-based cathode materials for the high-powered rechargeable aqueous ZIBs. [ABSTRACT FROM AUTHOR]