Magnetically Aligned Low‐Tortuosity Electrode for High‐Performance Pouch Pseudocapacitor with Commercial‐Level Mass Loading

Abstract The industrial production and application demand a more powerful energy storage capacity. Nevertheless, when the mass loading of active electrode materials rises, the consequent high distortion and low conductivity may result in the reduction of the utilization rate of active materials. To ensure electrodes with a state of “high performance” and “commercial‐level mass loading”, this study synthesizes an oxygen‐vacancy (O V )‐rich Ni‐Co@Ni‐Co compound chains with low‐tortuosity by using a magnetic field‐assisted chemical reduction method. When the mass loading reaches 10 mg cm −2 , the electrode exhibits an unprecedented ultra‐high capacitance of 1339 F g −1 (148.8 mAh g −1 ). The assembled symmetrical supercapacitor with a total mass loading of 20 mg cm −2 can achieve an energy density of up to 28.51 Wh kg −1 . This work has also innovatively proposed a new flexible packaging process for supercapacitors. The pouch pseudocapacitor demonstrates an ultrahigh energy density (30.7 Wh kg −1 at a power density of 800 W kg −1 ) and excellent cycling stability (60.0% capacitance retention after 10 000 cycles). Moreover, the supercapacitor pack assembled with three individual pouch pseudocapacitors can stably charge a smartphone for up to 2 minutes and 40 seconds, which hasn't been reported till now, representing a great breakthrough in practical supercapacitor applications.