Stabilizing the Mn4+/Mn3+ redox at 2.7 V plateau in LiNi0.5Mn1.5O4 cathode material for high energy density and long cycle lifetime via Mo6+ doping

The appeal for high-energy applications of LiNi0.5Mn1.5O4 (LNMO) cathode material has progressively diminished due to its inherently limited energy storage capability. In this investigation, Mo doping in LNMO cathode was utilized to enhance both electronic and ionic conductivities, resulting in stabilized redox of Mn4+/Mn3+ at 2.7 V plateau that contributes high energy density and long cyclic performance. As a result, significant enhancements in specific capacity and cycling performance were achieved during cycling tests at 2-5 V. Following 100 charge-discharge cycles at 1C rate, the discharge specific capacity diminished from 209.9 to 178.8 mAh g(-1), with a capacity retention of 85.2 %, while the un-doped sample only present a value of 45.4 %. The exceptional longer cycling performance could be ascribed to the improved electronic structure, which arises from a narrowed bandgap and thereby boosts electronic conductivity. Furthermore, Mo doping results in an elongation of the Li-O bond, which expands the volume of the LiO4 tetrahedra and contributes to an increase in the Li+ diffusion coefficient from 4.726 x 10(-13) to 2.112 x 10(-12) cm(2) S-1. The Mo-doped sample offered a discharge capacity of 166.6 mAh g(-1) at a 2C rate, in stark contrast to the mere 123 mAh g(-1) exhibited by the undoped sample. Among all investigated samples, LiNi0.5Mn1.49Mo0.01O4 demonstrated outstanding energy density of 796 Wh kg(-1), showing high potential in the field of high energy storage.