Solid State Ionics ( IF 3.0 ) Pub Date : 2021-07-23 , DOI: 10.1016/j.ssi.2021.115714 Zhi-Teng Wang 1, 2, 3 , Ran-Cheng Wang 1, 2, 3 , Lin-Bo Tang 1, 2, 3 , Yun-Jiao Li 1, 2, 3 , Jing Mao 4 , Ke-Hua Dai 5 , Zhen-Jiang He 1, 2, 3 , Jun-Chao Zheng 1, 2, 3
In spite of its high theoretical capacity and plentiful sources, the commercial application of vanadium dioxide is still unpractical because of its poor electrical conductivity and drastic volume changes during lithium-ion storage, resulting in poor electrochemical performance and fast capacity decay. To overcome these disadvantages, a newly 2D material, named Ti3C2 MXenes, is introduced to VO2 as a 3D framework via electrostatic attraction, forming Ti3C2@VO2 composite with a sandwich-like architecture. In the Ti3C2@VO2 composite, Ti3C2 play a role of three-dimensional matrix which not only strengthen the electron conductivity but also suppress the drastic volume changes of VO2 within the process of lithiation and de-lithiation. Meanwhile, VO2 nano particles growing between the layers of Ti3C2 act as the pillar to prevent multilayer Ti3C2 nanosheets from stacking and structure collapse. Consequently, the Ti3C2@VO2 composite exhibit better electrochemical performance and tiny volume swelling (a capacity of 365.6 mAh g−1 and a volume expansibility of 18.3% after 100 cycles at a current density of 100 mA g−1) than pure VO2. In addition, the pseudocapacitive contribution ratio is 57.4 at a scan rate of 2 mV s−1, which benefit from the sandwich-like structure with large surface and active sites, leading to better rate performance.
中文翻译:
一种通过水热法合成的用于储锂的三明治状 Ti 3 C 2 @VO 2复合材料
尽管二氧化钒理论容量高、来源丰富,但由于其导电性差、锂离子存储过程中体积变化剧烈,导致电化学性能差、容量衰减快,因此其商业应用仍然不切实际。为了克服这些缺点,一种名为 Ti 3 C 2 MXenes的新型 2D 材料通过静电引力引入 VO 2作为 3D 框架,形成具有三明治结构的Ti 3 C 2 @VO 2复合材料。在 Ti 3 C 2 @VO 2复合材料中,Ti 3 C 2发挥三维基体的作用,不仅增强了电子导电性,而且抑制了锂化和脱锂过程中VO 2的剧烈体积变化。同时,生长在Ti 3 C 2层间的VO 2纳米颗粒作为支柱,防止多层Ti 3 C 2纳米片堆叠和结构坍塌。因此,Ti 3 C 2 @VO 2复合材料表现出更好的电化学性能和微小的体积膨胀(容量为 365.6 mAh g -1,在 100 mA g -1的电流密度下循环 100 次后体积膨胀率为 18.3%−1 ) 比纯 VO 2。此外,在2 mV s -1的扫描速率下赝电容贡献率为57.4 ,这受益于具有大表面和活性位点的三明治状结构,导致更好的倍率性能。