Constructing ultrahigh capacitance (Co,Mn)(Co,Mn)2O4/Ni(OH)2 electrode for boosted all-solid-state fiber asymmetric supercapacitors

To meet the practical demands of flexible fiber-shaped supercapacitors (FSSCs) for wearable electronics, it's crucial to develop electrodes with both high energy density and flexibility. In this work, an ultrahigh capacitance (Co,Mn) (Co,Mn)2O4/Ni(OH)2 (CMO/Ni(OH)2) fiber electrode is designed. The (Co,Mn)(Co,Mn)2O4 (CMO) nanosheets possessing large specific surface area and enriched active sites, which can be served as nano-substrate for the electrodeposition of Ni(OH)2. This special structure facilitates the exposure of more electroactive sites and accelerate rapid electrons transfer, resulting in boosted electrochemical performance. Benefiting from these advantages, the area capacitance of the CMO/Ni(OH)2 electrode is up to 4787.6 mF cm- 2 at 1 mA cm- 2 , which is approximately 15 times higher than that of the CMO (311 mF cm- 2 ), and 6.7 times higher than that of the Ni(OH)2 (718 mF cm- 2 ). Coupled with activated carbon (AC) electrode, the assembled all-solid-state CMO/Ni(OH)2//AC FSSCs demonstrate a high energy density of 89.45 mu W h cm- 2 at 1505 mu W cm- 2 , along with great flexibility and stability. Moreover, these devices can be integrated into clothes, and electronic watch, serving as an energy supply. This work offers a novel approach to designing high-performance fiber electrode for wearable flexible energy storage devices.