Wei Yi, Zhang Peng, Zhou Shujie, Tian Xue, Soomro Razium Ali, Liu Huan, Du Huiling, Xu Bin
State Key Laboratory of Organic-Inorganic Composites, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing, 100029, China.
Henan Key Laboratory of Quantum Materials and Quantum Energy, School of Quantum Information Future Technology, Henan University, Zhengzhou, 450046, China.
Small. 2024 Jul;20(30):e2306541. doi: 10.1002/smll.202306541. Epub 2024 Feb 26.
Bismuth (Bi) is regarded as a promising anode material for potassium ion batteries (PIBs) due to its high theoretical capacity, but the huge volume expansion during potassiation and intrinsic low conductivity cause poor cycle stability and rate capability. Herein, a unique Bi nanoparticles/reduced graphene oxide (rGO) composite is fabricated by anchoring the Bi nanoparticles over the rGO substrate through a ball-milling and thermal reduction process. As depicted by the in-depth XPS analysis, strong interfacial Bi-C bonding can be formed between Bi and rGO, which is beneficial for alleviating the huge volume expansion of Bi during potassiation, restraining the aggregation of Bi nanoparticles and promoting the interfacial charge transfer. Theoretical calculation reveals the positive effect of rGO to enhance the potassium adsorption capability and interfacial electron transfer as well as reduce the diffusion energy barrier in the Bi/rGO composite. Thereby, the Bi/rGO composite exhibits excellent potassium storage performances in terms of high capacity (384.8 mAh g at 50 mA g), excellent cycling stability (197.7 mAh g after 1000 cycles at 500 mA g with no capacity decay) and superior rate capability (55.6 mAh g at 2 A g), demonstrating its great potential as an anode material for PIBs.
铋（Bi）因其高理论容量而被视为钾离子电池（PIB）颇具前景的负极材料，但其在钾化过程中巨大的体积膨胀以及固有的低电导率导致循环稳定性和倍率性能较差。在此，通过球磨和热还原工艺将铋纳米颗粒锚定在还原氧化石墨烯（rGO）基底上，制备了一种独特的铋纳米颗粒/还原氧化石墨烯（Bi/rGO）复合材料。如深入的XPS分析所示，铋与rGO之间可形成强界面Bi-C键，这有利于缓解铋在钾化过程中的巨大体积膨胀，抑制铋纳米颗粒的聚集，并促进界面电荷转移。理论计算揭示了rGO对增强铋/还原氧化石墨烯复合材料中钾吸附能力、界面电子转移以及降低扩散能垒的积极作用。因此，Bi/rGO复合材料在高容量（50 mA g时为384.8 mAh g）、优异的循环稳定性（500 mA g下1000次循环后为197.7 mAh g，无容量衰减）和卓越的倍率性能（2 A g时为55.6 mAh g）方面表现出优异的储钾性能，证明了其作为PIB负极材料的巨大潜力。
