Interface metallization enabled an ultra-stable Fe 2 O 3 hierarchical anode for pseudocapacitors.

Despite significant advances in cathode materials, developing high-performance anodes remains a key challenge for future pseudocapacitors. Fe 2 O 3 has been considered as a promising anode candidate due to its high theoretical capacitance, environmental benignity, and earth-abundant characteristics. However, the low electronic conductivity and poor cyclability of Fe 2 O 3 significantly limit its practical application. In this work, a 3D nickel-metalized carbon nanofiber network was developed to deposit an Fe 2 O 3 nanosheet anode. The nickel layer not only improved the electronic conductivity and the wettability of the 3D carbon substrate but also benefit the stability of the Fe 2 O 3 /carbon interfaces and the stress-release upon cycling. As a result, the newly designed Fe 2 O 3 anode composite exhibited a high areal capacitance of 1.80 F cm -2 at a high mass loading of 4.2 mg cm -1 and ultra-high capacitance retention of 85.1% after successive 100 000 cycles, outperformed most of the reported Fe 2 O 3 -based anode materials. Extended the interface metallization method to a MnO 2 cathode, excellent capacitance retention of 108.2% was reached after 26 000 cycles, suggesting a potentially broad application of such an interface-management method in elevating the stability of metal oxide materials in various pseudocapacitive energy storage devices.