Liu Lei, Du Zhuzhu, Wang Jiaqi, Du Hongfang, Wu Sheng, Li Mengjun, Zhang Yixuan, Sun Jinmeng, Sun Zhipeng, Ai Wei
Frontiers Science Center for Flexible Electronics (FSCFE) and Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China.
Fujian Cross Strait Institute of Flexible Electronics (Future Technologies), Fujian Normal University, Fuzhou 350117, China.
Research (Wash D C). 2023 Aug 16;6:0209. doi: 10.34133/research.0209. eCollection 2023.
Soft carbons have attracted extensive interests as competitive anodes for fast-charging sodium-ion batteries (SIBs); however, the high-rate performance is still restricted by their large ion migration barriers and sluggish reaction kinetics. Herein, we show a molecular design approach toward the fabrication of nitrogen and phosphorus codoped mesoporous soft carbon (NPSC). The key to this strategy lies in the chemical cross-linking reaction between polyphosphoric acid and p-phenylenediamine, associated with pyrolysis induced in-situ self-activation that creates mesoporous structures and rich heteroatoms within the carbon matrix. Thanks to the enlarged interlayer spacing, reduced ion diffusion length, and plentiful active sites, the obtained NPSC delivers a superb rate capacity of 215 mAh g at 10 A g and an ultralong cycle life of 4,700 cycles at 5 A g. Remarkably, the full cell shows 99% capacity retention during 100 continuous cycles, and maximum energy and power densities of 191 Wh kg and 9.2 kW kg, respectively. We believe that such a synthetic protocol could pave a novel venue to develop soft carbons with unique properties for advanced SIBs.
软碳作为快速充电钠离子电池（SIBs）的竞争性负极材料已引起广泛关注；然而，其高倍率性能仍受限于较大的离子迁移势垒和缓慢的反应动力学。在此，我们展示了一种制备氮磷共掺杂介孔软碳（NPSC）的分子设计方法。该策略的关键在于多磷酸与对苯二胺之间的化学交联反应，以及热解诱导的原位自活化，这在碳基质中形成了介孔结构和丰富的杂原子。得益于扩大的层间距、缩短的离子扩散长度和丰富的活性位点，所制备的NPSC在10 A g下具有215 mAh g的优异倍率容量，在5 A g下具有4700次循环的超长循环寿命。值得注意的是，全电池在100次连续循环中容量保持率为99%，最大能量密度和功率密度分别为191 Wh kg和9.2 kW kg。我们相信，这样的合成方案可为开发具有独特性能的先进SIBs软碳开辟一条新途径。
