Lashari Najeeb Ur Rehman, Zhao Mingshu, Zheng Qingyang, Duan Wenyuan, Song Xiaoping
School of Science, Key Laboratory of Shaanxi for Advanced Functional Materials and Mesoscopic Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, Xi'an, 710049, Shaanxi, China.
Xi'an High Tech Res Inst, Xi'an 710025, Shaanxi, China.
Dalton Trans. 2019 Sep 7;48(33):12591-12597. doi: 10.1039/c9dt02490e. Epub 2019 Aug 1.
An aqueous rechargeable lithium-ion battery (ARLB) system has been assembled using as-prepared polypyrrole (PPy) to coat NaKKO (NKVO) anode coupled with LiMnO cathode, both immersed in an aqueous LiNO solution. The chemical polymerization techniques have been employed to uniformly coat the surface of NKVO with PPy. The phase of NKVO@PPy composite has been characterized by X-ray diffraction; for quantifying PPy content, the thermal gravimetric analysis was performed. Spectroscopy techniques have been used to visualize the microscale morphological changes on the particle surface of NKVO caused by PPy coating. The staircase cyclic voltammetry and galvanic charge-discharge tests have been conducted at various current rates in the voltage range of -1 to 1 V vs. saturated calomel electrode (SCE). The PPy coated NKVO material showed a similar intercalation/deintercalation mechanism to that of pristine NKVO. When subjected to cyclic performance evaluation at a higher rate of 4 A g, PPy-coated NKVO@PPy exhibited a preliminary discharge capacity of 115 mA h g and 64.5 mA h g following 400 cycles of charge-discharge with a retention rate of 55.6%, whereas the uncoated NKVO showed only 18.8% capacity retention rate. The significantly improved cyclic capacity retention has been attributed to the PPy coating, which acted as a protective layer preventing the unwanted side reactions, buffering the volume change and simultaneously increasing the electrical conductivity of pristine NKVO electrode during charge-discharge cycles. The decent performance demonstrated that NKVO@PPy is a promising electrode material for ARLB.
采用制备好的聚吡咯（PPy）包覆NaKKO（NKVO）阳极与LiMnO阴极组装了水系可充电锂离子电池（ARLB）系统，二者均浸没在LiNO水溶液中。采用化学聚合技术用PPy均匀包覆NKVO表面。通过X射线衍射对NKVO@PPy复合材料的物相进行了表征；为了定量PPy含量，进行了热重分析。利用光谱技术观察了PPy包覆引起的NKVO颗粒表面微观形态变化。在相对于饱和甘汞电极（SCE）的-1至1 V电压范围内，以不同电流速率进行了阶梯循环伏安法和恒流充放电测试。PPy包覆的NKVO材料表现出与原始NKVO相似的嵌入/脱嵌机制。当以4 A g的较高倍率进行循环性能评估时，PPy包覆的NKVO@PPy在400次充放电循环后的首次放电容量为115 mA h g，后续放电容量为64.5 mA h g，保留率为55.6%，而未包覆的NKVO仅表现出18.8%的容量保留率。循环容量保留率的显著提高归因于PPy包覆层，它起到了保护层的作用，防止了不必要的副反应，缓冲了体积变化，并在充放电循环过程中同时提高了原始NKVO电极的电导率。良好的性能表明NKVO@PPy是一种有前途的ARLB电极材料。
