Carbonyl compounds as cathode materials for lithium-ion batteries
Choo, Kenneth Wei Jie
Date of Issue2017
School of Materials Science and Engineering
Organic compounds as active electrode materials are known for their low cost, versatility, renewability and eco-friendliness. Carbonyl compounds with large aromatic structure and heteroatoms have proven to achieve long cycling stability and high specific capacity. In this report, a novel carbonyl compound with heteroatoms and large aromatic structures (PDA-4N) was investigated as cathode material for lithium-ion battery. Electrochemical properties of PDA-4N of different weight ratio and NTCDA were evaluated and discussed. The active materials were well blended with CNT additive and PVDF binder before establishing a coin-type cell configuration for analyses on cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), rate performance, cycling performance and charge-discharge capacity profile. Investigations on electrochemical performances of PDA-4N were conducted between 2.0 and 3.9V vs. Li/Li+. PDA-4N demonstrated a reasonably high initial specific capacity of 116.3 mAh g-1 and rate performance up to current rate of 7.92C. PDA-4N also exhibited a stable cycling performance of 50 cycles with reasonable capacity retention of 78.7% of its theoretical capacity and a high coulombic efficiency of 99.86% on average. However, EIS measurement revealed that PDA-4N possessed slow charge transfer capability and poor electric response. Further studies on CNT additive and PVDF binder ratio illustrated a positive effect on cycling stability of PDA-4N. This study reveals that carbonyl compound with heteroatoms and large aromatic structures could potentially be utilised as organic cathode material for rechargeable lithium-ion battery and effective modifications can be made to further enhance the electrochemical properties.
Final Year Project (FYP)
Nanyang Technological University