核-鞘结构碳纳米管@硫杂环苯醌聚合物的锌离子电池性能研究

Core-sheath structured carbon nanotube@surlfure heterocyclic quinone polymer composites for high-performance zinc-ion batteries

关键词:  核-鞘结构  水系锌离子电池  硫杂环醌类聚合物  复合材料  电极材料  MWCNT

Key words:  nucleo-shell structure  water zinc-ion battery  thioheterocyclic quinone polymer  composite material  electrode material  MWCNT

摘要:

苯醌聚合物具有结构可调、容量大、电化学可逆性好等优点,被认为是构建高能水锌离子电池(AZIB)最合适的正极材料。然而,苯醌聚合物的Zn^{2+存储性能往往受到电子导电性低和离子扩散缓慢的限制。采用原位界面聚合方法,以四氯对苯醌和硫化钠为低成本聚合物前体,多壁碳纳米管(MWCNT)为导电载体,成功制备了一种新型MWCNT@硫杂环醌类聚合物(MWCNT@SHQP)无机-有机纳米复合材料。SHQP与CNT之间的π-π堆叠相互作用在聚合过程中使聚合物在MWCNT四周生长,确保SHQP层的超薄核-鞘纳米结构的形成。MWCNT@SHQPs独特的纳米结构可以提高SHQP聚合物的电子导电性,增加电荷存储的活性羰基(C[FY=,1]O)基团,促进Zn2+}扩散,缓冲体积变化,抑制充放电过程中SHQP聚合物的溶解。MWCNT@SHQP材料表现出较高的放电容量(在100 mA/g电流密度下为185 mAh/g),优异的倍率能力(在5 A/g时为100.3 mAh/g)和长循环稳定性(在1.5 A/g下循环2 000次后容量保持88.7%)。研究表明,制备苯醌聚合物复合碳纳米管正极材料(MWCNT@polymer)是提高苯醌聚合物锌离子电池电荷存储性能的有效途径。

Abstract:

Quinone polymers with the advantages of structure tunability, large capacity and good electrochemical reversibility are considered as highly promising cathode materials for high-energy aqueous zinc-ion batteries (AZIBs). However, their Zn²⁺ storage performance is limited by low electronic conductivity and slow ion diffusion.In this study, we synthesized a novel multiwalled carbon nanotube@sulfur heterocyclic quinone polymer (MWCNT@SHQP) inorganic-organic nanocomposite material via an in-situ interfacial polymerization method. This approach utilized tetrachloroperoxyquinone and sodium sulfide as low-cost polymer precursors with MWCNT as conductive support. The π-π stacking interaction between the SHQP and MWCNT facilitated the polymer growth around the MWCNTs during the polymerization process, ensuring the formation of a core-sheath nanostructure. This unique nanostructure of MWCNT@SHQPs improves the electronic conductivity of the SHQP polymer, increases the availability of active carbonyl (C[FY=,1]O) groups for charge storage, promotes Zn²⁺ diffusion, mitigates volume fluctuations, and inhibits the dissolution of SHQP polymer during cycling. The MWCNT@SHQP cathode exhibits high discharge capacity (185 mAh/g at 100 mA/g), excellent rate capability (100.3 mAh/g at 5 A/g), and long cycling stability (88.7% capacity retention after 2 000 cycles at 1.5 A/g).The study indicates that designing multi-walled carbon nanotube@benzoquinone polymer composite cathode materials (MWCNT@polymer) is an effective approach to enhance the charge storage performance of benzoquinone polymer zinc-ion batteries.