In Situ Construction of the Coral-like Polyaniline on the Aligned Silicon Nanowire Arrays for Silicon Substrate On-chip Supercapacitors

Abstract

Silicon substrate on-chip (SSOC) supercapacitors have recently attracted considerable attention in electronic devices because of their compatibility with the current silicon-based micro- and nanofabrication processes. However, the low-energy density of the silicon substrate supercapacitors largely restricts their practical applications. Herein, in situ polymerization of coral-like polyaniline (PANI) was performed over the surfaces of aligned silicon nanowires (SiNWs) prepared by the metal-assisted chemical etching process. Especially, the coral-like morphology of the PANI over the aligned SiNWs (PANI@SiNWs) is regulatable with the control of the concentration of the aniline monomer. After systematical structural characterization of PANI@SiNWs by field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectrometry, and Raman spectroscopy, it is confirmed that the coral-like morphology provides higher specific surface area and more effective charge transport channels, which essentially benefits the exchange of the aqueous electrolytes on the surface of the electrode to improve the electrochemical performances of the material. Therefore, compared to individual PANI and SiNWs, the prepared PANI@SiNW-based supercapacitor electrode exhibited a much higher areal capacitance of ∼95 mF/cm2 at a scan rate of 10 mV/s. The obtained PANI@SiNW electrode exhibited reliable stable cyclability with a capacitance retention of 71.8% of the initial value compared with pure PANI. The presented work demonstrates a feasible approach to improve the areal capacitance value of SSOC supercapacitors.

Scalable Construction of Flexible Composite Textile Electrodes through In Situ Growth of Polyaniline Nanofibers on Carbon Cloths under Electric Field toward High Areal Capacitance Supercapacitors

“…The specific capacitance of the electrode was 398.6, 726.8, 859.7, 1203.3, and 1175.0 mF cm –2 , while the rate retention was 73.3%, 75.4%, 83.8%, 84.6%, and 83.1% for the aniline concentrations of 0.2, 0.5, 0.8, 1.0, and 1.3 M, respectively. The maximum areal capacitance of composite textile electrode fabricated at 1.0 M aniline concentration was 1203.3 mF cm –2 at the scan rate of at 5 mV s –1 , being larger than 246 mF cm –2 at 5 mV s –1 for PANi/graphene/cotton and 95.2 mF cm –2 at 10 mV s –1 for PANi/silicon nanowire arrays . Remarkably, even when the scan rate increased to 100 mV s –1 , the areal capacitance of up to 1018.0 mF cm –2 remained, corresponding to 84.6% capacitance retention.…”

“…Remarkably, even when the scan rate increased to 100 mV s –1 , the areal capacitance of up to 1018.0 mF cm –2 remained, corresponding to 84.6% capacitance retention. Such retention was better than 84.0% (5–100 mV s –1 ) for PANi nanofiber arrays/carbon cloth, 28.4% (5–100 mV s –1 ) for PANi/graphene/cotton, and 38.9% (10–100 mV s –1 ) for PANi/silicon nanowire arrays . Directly growing PANi on carbon cloth is beneficial for enhancing the rate capability.…”

“…On the basis of the analysis of CV curves, the mechanism for charge storage was further discussed (see Figures S2 & S3 in the Supporting Information). The areal capacitance ( C s ) can be estimated from the CV curves according to the equation C s = ∫( I d V )/( S × 2 ×Δ V × s ), where I is the response current, S is the electroactive surface area of the electrode, s is the scan rate, V is the potential, and Δ V is the potential window in the CV curve. The specific capacitance of the electrode was 398.6, 726.8, 859.7, 1203.3, and 1175.0 mF cm –2 , while the rate retention was 73.3%, 75.4%, 83.8%, 84.6%, and 83.1% for the aniline concentrations of 0.2, 0.5, 0.8, 1.0, and 1.3 M, respectively.…”

An improved bioinspired strategy to construct nitrogen and phosphorus dual-doped network porous carbon with boosted kinetics potassium ion capacitors

“…55 The synergistic effect between the highly-graded mesoporous/microporous porous structure and the nanosheet can reversibly capture more ions through the surface adsorption or redox reaction of NPMC-700, which further enhances its surface capacitive contribution. 15,56,57…”

Electrodeposition Polyaniline Nanofiber on the PEDOT:PSS-Coated SiNWs for High Performance Supercapacitors

“…Li, et al [32] prepared the graphene@SiNWs electrode combined with pseudocapacitive polyaniline coating, which showed a large specific capacitance of 185 mF cm -2 . Liu, et al [33] synthesized coral-like polyaniline over the surfaces of aligned SiNWs via an in-situ polymerization method. The as-prepared electrode exhibited an areal capacitance of ∼95 mF cm -2 at a scan rate of 10 mV s -1 .…”