北京服装学院《ACS AEM》：多级多孔MXene QD/石墨烯复合纤维，用于高性能超级电容器

图1.MQDs@PGF的制造示意图。

图 2. Surface SEM images of (a, b) GF, (c, d) PGF-10, and (e, f) PGF-15. (g) GCD curves of GF, PGF-10, and PGF-15 at 0.2 mA cm –2 and (h) CV curves at 10 mV s –1 in H 2 SO 4 /PVA gel electrolyte.

图3. TEM of (a) GO sheets, (b) MXene sheets, and (c, d) MQDs. SEM images of (e, f) surfaces and (g, h) cross sections of MQDs@PGF; EDS mapping of (i–l) MQDs@PGF.

图4. (a) XRD patterns of MQDs@PGF, PGF-15, Ti 3 C 2 T x films, and Ti 3 AlC 2 powders. (b) Pore size distribution and nitrogen adsorption desorption curves of MQDs@PGF. (c–f) XPS patterns of MQDs@PGF.

图5. Electrochemical performance of PGF-15 and MQDs@PGF assembled fiber-based supercapacitors in H 2 SO 4 /PVA gel electrolyte. (a) GCD curves and (d) CV curves of MQDs@PGF. (b) GCD curves, (c) specific areal capacitance, (e) CV curves, and (f) EIS curves of PGF-15 and MQDs@PGF.

图6. Electrochemical performance of PGF-15 and MQDs@PGF-assembled fiber-based supercapacitors. (a) GCD curves and (e) CV curves of MQDs@PGF FSCs. (b) GCD curves. (c) Specific areal capacitance. (d) Energy density comparison. (f) CV curves of PGF-15 and MQDs@PGF.

图7. (a) Capacitance retention of MQDs@PGF FSCs after 9000 cycles and GCD curves for the last 10 cycles. (b) Plots of energy density and power density of MQDs@PGF FSCs compared to other fiber-based supercapacitors. (c) CV curves of MQDs@PGF FSCs under bending 0, 45, 90, 135, and 180° at 100 mV s –1 and the application photos of five MQDs@PGF FSCs connected in series to supply energy for (d) timer and (e) alarm clock.

综上所述，采用同轴微流体纺丝技术和气体发泡方法制备了具有分层多孔网络结构的MQDs/石墨烯复合纤维（MQDs@PGF）。将0D MQDs作为电化学活性纳米材料插层到二维石墨烯纳米片中以增大层间间距，并使用发泡剂NH4HCO3在复合纤维中生成大量均匀的分层互连多孔网络结构。通过结合物理插层、电活性材料耦合和化学气体发泡技术，复合纤维获得了丰富的离子通道（微介质-宏孔）和较大的比表面积（68.8 m2 g-1），从而获得了 1288 mF cm-2 的高比面积电容和 147.5 μWh cm-2 的优异能量密度。经过 9000 次循环后，电容量保持率接近 95%，并且在不同弯曲角度下的电化学性能几乎没有变化。制备的 MQDs@PGF FSCs 可为实际应用中的微电子器件稳定供电。这项工作为电极材料的结构设计提供了一种新策略，从而实现可穿戴便携设备的高效储能。