Moon Hyunseok, Kim Jung-Hui, Yao Nan, Ryou Myeong-Hwa, Chen Xiang, Park Yeonju, Han Sun-Phil, Bak Cheol, Kang Hyunseo, Lee Yong Min, Jung Young Mee, Zhang Qiang, Lee Sang-Young
Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Tsinghua Center for Green Chemical Engineering Electrification (CCEE), Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China.
Adv Mater. 2025 Jun;37(22):e2414335. doi: 10.1002/adma.202414335. Epub 2025 Apr 7.
Despite their potential as an alternative to commercial lithium (Li)‒ion batteries, Li-sulfur (Li-S) batteries face challenges related to energy density limitations caused by the considerable amount of electrolyte required. Lean electrolytes have proven effective in mitigating this issue. However, they tend to exacerbate Li polysulfides (LiPS) clustering, resulting in incomplete S utilization and sluggish conversion kinetics. Here, 2,2,6,6-tetramethylpiperidin-1-oxyl radical (TEMPO)-oxidized cellulose nanofiber (TOCN) is presented as an expanded nanofibrous electrode binder for lean-electrolyte Li‒S batteries. Owing to its 1D fibrous structure and expanded inter-glucose chain distance, the TOCN binder offers more accessible active sites for intermolecular interactions with LiPS. Consequently, LiPS cluster formation is effectively suppressed even at a low TOCN binder content of 1 wt%, while a high S loading of 72 wt% is achieved. The resulting S cathode with the TOCN binder enables Li‒S cells to exhibit a remarkable specific capacity of 1221 mAh g under constrained electrolyte conditions (low electrolyte-to-sulfur ratio of 2.0 µL mg and low density of 0.927 g mL), yielding a high cell-level energy density of 503 Wh kg that surpasses those of previously reported S cathodes based on conventional synthetic polymer binders.
尽管锂硫（Li-S）电池有潜力成为商用锂离子电池的替代品，但由于需要大量电解质，面临着与能量密度限制相关的挑战。贫电解质已被证明能有效缓解这一问题。然而，它们往往会加剧多硫化锂（LiPS）的聚集，导致硫利用率不高和转化动力学缓慢。在此，2,2,6,6-四甲基哌啶-1-氧基自由基（TEMPO）氧化的纤维素纳米纤维（TOCN）被用作贫电解质Li-S电池的膨胀纳米纤维电极粘结剂。由于其一维纤维结构和葡萄糖链间距离的扩大，TOCN粘结剂为与LiPS的分子间相互作用提供了更多可及的活性位点。因此，即使在低至1 wt%的TOCN粘结剂含量下，LiPS簇的形成也能得到有效抑制，同时实现了72 wt%的高硫负载量。所得含TOCN粘结剂的硫正极使Li-S电池在受限电解质条件下（低电解质与硫比为2.0 μL mg 且低密度为0.927 g mL）表现出1221 mAh g的显著比容量，产生503 Wh kg的高电池级能量密度，超过了先前报道的基于传统合成聚合物粘结剂的硫正极。
