Investigations about the Use and the Degradation Mechanism of LiNi0.5Mn1.5O4in a High Power LIC

The manuscript reports the performance of a hybrid device containing the spinel positive electrode material LiNi 0.5 Mn 1.5 O 4 (LNMO). The LNMO samples were synthesized via a sol-gel process with a post thermal treatment at 1000°C and then combined against an activated carbon negative electrode. The obtained device shows excellent cycling stability as well as good electrochemical performance at a current rate of 600 mA g −1 (corresponds to 10C for LNMO) in a cell voltage range of 3.3 V which is significantly high voltage among reported lithium intercalation cathode-based lithium-ion capacitors (LIC). With constant current cycling at 600 mA g −1 , the LIC delivered a promising capacity retention of 89% even after 4,000 cycles with average specific energy and power of about ∼50 Wh kg −1 and ∼1100 W kg −1 .