Investigating the influences of lanthanum-based perovskite oxides on NiCo2S4 as electrode material in activated carbon cloth-based flexible supercapacitors

Abstract

We investigated the potential enhancement of flexible supercapacitor (FSC) performance through the combination of different La-based perovskite nanostructures (LaMO₃, where M denotes Ni, Co, and Fe) with NiCo₂S₄ (NCS) as electrode material. NCS was mixed with LaMO₃ at a 1:1 M ratio and three composite electrode materials of NCS/LNO, NCS/LCO, and NCS/LFO were obtained, which were individually coated on the activated carbon cloth (ACC) to prepare flexible electrodes. The structural and morphological features, along with elemental content of the synthesized materials and the prepared ACC-based electrodes were examined using different physicochemical characterization techniques. The composite electrodes exhibited superior electrochemical performance than NCS, in which NCS/LNO, NCS/LCO, NCS/LFO, and NCS exhibited an initial capacity of 585, 500, 410, and 330C/g, respectively, under an applied 1 A/g current density. NCS/LNO featured a charge maintenance of 87.5 % at 4 A/g after 10,000 cycles, which was higher than that achieved for NCS/LCO (82 %), NCS/LFO (76.4 %), and NCS (71 %). Subsequently, four asymmetric SC devices were constructed with the aforementioned electrodes serving as the anode and activated carbon (AC) as the cathode. In comparison to other three devices, the NCS/LNO//AC device greatly improved power and energy density, reaching a maximum of 86.6 Wh.kg⁻¹ at a power density of 400 W.kg⁻¹, which was higher than the desired 39.5 Wh.kg⁻¹ even at a high-power density of 16 kW.kg⁻¹. Moreover, when subjected to 10,000 cycles at a current density of 4 A/g, this device maintained 85 % of its capacity. Furthermore, the FSC device fabricated based on NCS/LNO could retain its electrochemical performance under bending deformation. This highlights that NCS/LNO can be regarded as a potential material with great promise for flexible energy systems and wearable electronics.