电化学
拉曼光谱
材料科学
涂层
分析化学(期刊)
纳米颗粒
极化(电化学)
箔法
集电器
碳纤维
介电谱
化学工程
纳米技术
化学
复合材料
电极
电解质
物理
物理化学
色谱法
复合数
光学
工程类
作者
Pravati Swain,M. Viji,Pavana S. V. Mocherla,C. Sudakar
标识
DOI:10.1016/j.jpowsour.2015.05.110
摘要
The charging/discharging cycles, rate capabilities, cyclic voltammetry and electrochemical impedance spectra (EIS) of sol–gel prepared C-coated LiFePO4 (C-LFP-SG) and a commercial LiFePO4 (LFP-comm), in combination with two different current collectors, viz. Al foil and C-coated Al foil (Al–C) are studied. A flat voltage profile at ∼3.4 V was seen during the charging/discharging cycle of C-LFP-SG/Al. However, C-LFP-SG/Al–C showed a continuous decrease in voltage during discharging and an increase during charging cycles. On contrary, LFP-comm/Al–C showed a constant flat voltage profile, whereas LFP-comm/Al shows a slight decrease during the discharge. C-LFP-SG/Al and LFP-comm/Al–C cells exhibit better electrochemical performance compared to C-LFP-SG/Al–C and LFP-comm/Al respectively. This is also reflected from a direct correlation between the flat potential behavior and their rate capabilities. From EIS measurements, we discuss the effect of C-coating on the charge-transfer resistances of LFP nanoparticles and current collectors. Raman analysis of carbon modes in all the cathodes and current collectors reveal that a large contribution from sp2 bonded carbon gives better electrochemical properties. Increasing sp3-like disordered carbon at the C–C interface leads to large polarization effects during the charging and discharging cycles.
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