Understanding and Calibration of Charge Storage Mechanism in Cyclic Voltammetry Curves
Xiangjun Pu, Dong Zhao, Chenglong Fu, Zhongxue Chen, Shunan Cao, Chunsheng Wang, Yuliang Cao
Abstract
Abstract Noticeable pseudo‐capacitance behavior out of charge storage mechanism (CSM) has attracted intensive studies because it can provide both high energy density and large output power. Although cyclic voltammetry is recognized as the feasible electrochemical technique to determine it quantitatively in the previous works, the results are inferior due to uncertainty in the definitions and application conditions. Herein, three successive treatments, including de‐polarization, de‐residual and de‐background, as well as a non‐linear fitting algorithm are employed for the first time to calibrate the different CSM contribution of three typical cathode materials, LiFePO 4 , LiMn 2 O 4 and Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 , and achieve well‐separated physical capacitance, pseudo‐capacitance and diffusive contributions to the total capacity. This work can eliminate misunderstanding concepts and correct ambiguous results of the pseudo‐capacitance contribution and recognize the essence of CSM in electrode materials.