辐照交联制备低分子量聚丙烯腈纤维锂硫电池正极材料及其储硫机理 高等学校化学学报    2022, 43 (3): 20210632-.   DOI:10.7503/cjcu20210632

Fig.10 Rate performance curves(A) and charge?discharge curves in the second cycle(B) of the SPAN cathode with different cross?linking degrees

正文中引用本图/表的段落

图10示出了不同交联度SPAN正极材料的倍率性能及充放电曲线图. 由图10（A）可见， 由SPAN组装的电池在2C倍率下的放电比容量仅有362.2 mAh/g， 循环过程中随电流密度升高出现了严重的容量衰减， 随后当倍率恢复到0.1C时， 容量保持率为90%， 而由SPAN-IR200和SPAN-IR300组装的电池在电流密度不断升高的条件下， 其容量衰减的程度较SPAN电池明显减小， 在2C下的放电比容量均超过了SPAN电池， 且交联度最高的SPAN-IR300电池在2C倍率下的放电比容量达到483.1 mA·h/g， 当倍率恢复至0.1C时的容量保持率约为96%， 说明辐照交联所形成的规整度更高的结构在加快电子传导的同时增加了电池的稳定性. 图10（B）给出0.2C倍率下循环第二圈的充放电曲线. 3组电极材料均有一个倾斜的放电平台， SPAN电极材料的起始放电电压约为1.6 V， 随交联度的增加， SPAN-IR200和SPAN-IR300的起始放电电压均有升高， 分别约为1.8和1.9 V. 由图10（B）曲线可知， 交联度最高的SPAN-IR300电池的充放电电势差（ΔE）最小， 说明其充放电过程中产生的极化最小， 氧化-还原可逆性较好， 电极材料具有更利于电子传导的稳定结构， 辐照交联对提升电池放电电压及缓解电池极化具有积极作用.

本文的其它图/表

• Fig.1  SEM image of the profiled PAN fiberInset: cross?sectional image.
• Fig.2  Morphology(A) and gel fraction diagram(B) Irradiation under different irradiation doses
• Fig.3  Polarizing optical microscopy images of profiled PAN fibers at different temperatures and under different irradiation dosesIrradiation dose/kGy: (A₁—A₅) 0; (B₁—B₄) 200; (C₁—C₄) 250; (D₁—D₄) 300; (E₁—E₄) 350.Temperature/℃: (A₁—E₁) r.t.; (A₂—E₂) 220; (A₃—E₃) 250; (A₄—E₄) 270; (A₅) 290.
• Table 1  Elemental analysis of profiled PAN fibers with different cross-linking degrees
• Fig.4  FTIR(A) and ¹³C NMR(B) spectra of PAN fibers with different cross?linking degreesa. PAN； b. PAN?IR200； c. PAN?IR300.
• Scheme 1  Possible reaction sites and structures during PAN cross?linking
• Table 2  Elemental analysis of SPAN with different cross-linking degrees
• Fig.5  SEM images(A₁—C₁) and corresponding elemental mappings(A₂—A₄, B₂—B₄, C₂—C₄) of SPAN with different cross?linking degrees
• Fig.6  XRD patterns of SPAN with different cross?linking degrees
• Fig.7  FTIR(A) and Raman(B) spectra of SPAN with different cross?linking degrees
• Fig.8  S_2p (A—C) and N_1s (D—F) XPS spectra of SPAN with different cross?linking degrees(A, D) SPAN?IR300; (B, E) SPAN?IR200; (C, F) SPAN.
• Scheme 2  Structure diagram of cross?linking and vulcanization reaction
• Fig.9  Cycling performance(A) and electrochemical impedance spectra(B) of SPAN electrodes with different cross?linking degrees
• Fig.11  CV curves of the SPAN cathode with different cross?linking degrees(A) SPAN; (B) SPAN?IR200; (C) SPAN?IR300.