Surface/interface engineering strategy modulated electrode structure for a flexible quasi-solid-state fiber-shaped NiCo//Bi battery

Abstract

Fiber-shaped electrochemical energy-storage devices (FEESDs) with the merits of high volumetric performance and a long-cycling lifespan play a vital role in the rapid development of portable and wearable electronics. To achieve this goal, we fabricate flexible planar-integrated fiber NiCo//Bi batteries by employing the hierarchical NiCo2S4@NiCoSe2 nanosheet heterostructure evenly deposits on carbon nanotube fiber (CNTF) substrate (denoted as NiCo2S4@NiCoSe2/CNTF) as cathode, well-dispersed oxygen-deficient bismuth oxide (Od-Bi2O3) nanosheet arrays directly anchor on CNTF (denotes as Od-Bi2O3/CNTF) as the anode. The aqueous NiCo//Bi battery achieves an ultra-high volumetric capacity of 352.38 mAh/cm3 (areal capacity of 0.62 mAh/cm2) and an ultra-high energy density and power density of 560.6 mWh/cm3 and 17.0 W/cm3, respectively. Moreover, the quasi-solid-state fiber NiCo//Bi battery still delivers a high volumetric capacity of 43.9 mAh/cm3, with a remarkable volumetric performance (58.6 mWh/cm3, a power density of 11.5 W/cm3) and outstanding long-lifespan capability (∼81% capacity retention over 10,000 cycles). This device can also be bent at different angles without losing its function and supplying power for an LED bulb, suggesting good flexibility and practicality. Thus, our fiber NiCo//Bi battery concept will significantly enrich the choice of fiber-shaped energy sources for future portable/wearable electronics.