Single‐crystal spinel Li1.08Mn1.92O4 octahedra cathode covered with Li-ion permeable robust NMC thin-layer protection for high voltage lithium‐ion batteries

Abstract

An innovative cathode structure consisting of NMC, a Li-ion permeable coating on single crystal (SC) of Li-rich Li1.08Mn1.92O4 (NMC@SC LR-LMO) cathode is reported for first-time as a multifunctional cathode material for Li-ion batteries. The purpose of NMC coating is to protect the active material from acid corrosion while excess Li in LMO crystallite has been added intentionally to increase the structural stability and to mitigate the irreversible phase transitions. At 0.5 C-rate, this NMC@SC LR-LMO cathode vs. Li metal anode provides a stable reversible specific capacity of 115 m Ah g–1 with an energy density of 460 W h kg–1 for 500 cycles. At 60 °C, a stable reversible specific capacity of 113 m Ah g–1 at 0.2 C-rate ensuring energy density of 452 W h kg–1 after 100 cycles is obtained. Full-cell of NMC@SC LR-LMO cathode and MCMB anode exhibit the capacity of 1.23 m Ah cm–2, 95.3% capacity retention even after 100 cycles at 0.44 mA cm–2/ 29.3 m Ah g–1, and the trend is maintained till 500 cycles. Finally, a pouch cell of NMC@SC LR-LMO cathode and MCMB anode of ∼38 m Ah is tested with a reversible areal capacity of 1.27 m Ah cm–2/ 85 m Ah g–1 after 150 cycles.