Electrochemical behavior and cyclic fading mechanism of LiNi0.5Mn0.5O2 electrode in LiNO3 electrolyte
(Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education,
College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China)
College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China)
Abstract: Electrochemical behavior of layered LiNi0.5Mn0.5O2 in LiNO3 aqueous solution and its cyclic fading mechanism in electrolytes with different pH values were investigated. CV results show that LiNi0.5Mn0.5O2 has good electrochemical reversible behaviors in 5 mol/L LiNO3 solution. Meanwhile, the electrode in 5 mol/L LiNO3 with pH value of 12 demonstrates the best electrochemical stability. Based on the electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) results, it is proposed that suppressed charge-transfer resistance is the major reason, which is probably ascribed to the more stable electrode surface and less structure change.
Key words: lithium ion battery; LiNi0.5Mn0.5O2; cyclic fading mechanism; cyclic voltammetry; LiNO3 solution