High‐Voltage LiNi 0.45 Cr 0.1 Mn 1.45 O 4 Cathode with Superlong Cycle Performance for Wide Temperature Lithium‐Ion Batteries

Spinel LiNi 0.45 Cr 0.1 Mn 1.45 O 4 synthesized by a scalable solution route combined by high temperature calcination is investigated as cathode for ultralong‐life lithium‐ion batteries in a wide operating temperature range. Scanning electron microscopy reveals homogeneous microsized polyhedral morphology with highly exposed {100} and {111} surfaces. The most highlighted result is that LiNi 0.45 Cr 0.1 Mn 1.45 O 4 has extremely long cycle performance and high capacity retention at various temperatures (0, 25, 50 °C), indicating that Cr doping is a prospective approach to enable 5 V LiNi 0.5 Mn 1.5 O 4 (LNMO)‐based cathode materials with excellent cycling performances for commercial applications. After 1000 cycles, the capacity retention of LiNi 0.45 Cr 0.1 Mn 1.45 O 4 is 100.30% and 82.75% at 0 °C and 25 °C at 1 C rate, respectively. Notably, over 350 cycles at 50 °C, the capacity retention of LiNi 0.45 Cr 0.1 Mn 1.45 O 4 can maintain up to 91.49% at 1 C. All the values are comparable to pristine LNMO, which can be attributed to the elimination of Li y Ni 1− y O impurity phase, highly exposed {100} surfaces, less Mn 3+ ions, and enhancement of ion and electron conductivity by Cr doping. Furthermore, an assembled LiNi 0.45 Cr 0.1 Mn 1.45 O 4 /Li 4 Ti 5 O 12 full cell delivers an initial discharge capacity of 101 mA h g −1 , meanwhile the capacity retention is 82.07% after 100 cycles.