Pulse‐potential electrochemistry to boost real‐life application of pseudocapacitive dual‐doped polypyrrole

Abstract

Polypyrrole (PPy) is a very promising pseudocapacitive electrode material for supercapacitors. However, the poor electrochemical performances and cycling stability caused by volumetric change and counterion drain severely limited its practical application and commercialization. Herein, we present a pulsepotential polymerization strategy for uniformly depositing a dual-doped PPy with ordered and shorter molecular structure by balancing the concentration polarization. Such a strategy ensures more homogeneous stress distribution of PPy during ultralong cycling tests and improves the cycle stability. Moreover, the pulse-potential polymerized PPy with dual anion doping behavior induces enhanced protonation level and improved electrical conductivity, which boosting the charge transfer kinetics. Therefore, the as-synthesized PPy exhibits a remarkable capacitance performance (7250 mF/cm 2 @ 3 mA/cm 2 ), outstanding rate capability (3073 mF/cm 2 @ 200 mA/cm 2 ) and a long cycle life. The assembled symmetric and asymmetric supercapacitors (ASC) exhibit good energy densities (0.8 mWh/cm 2 for ASC and 0.5 mWh/cm 2 for symmetric supercapacitor), and excellent durability with zero capacitive loss after 35,000 cycles. In addition, we have fabricated small pouch devices, which can effectively operate a variety of electronic products (including the high-voltage 5 V smartphone, and tablet) and well withstand the external extreme tests during operation, demonstrating the quantitative investigation of the real-life application of aqueous supercapacitors.

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“…This depolarization effect will promote and improve the uniformity of the deposited layer. 24,25 Moreover, the application of an electrical pulse could induce irregular oscillations of dislocation nuclei and result in defect migration due to the interaction between electrons and dislocations. These oscillations also cause lattice distortion and residual stress, leading to slow relaxation of non-consistent twinning at the boundary within the electrical pulse gap.…”

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“…[1][2][3][4][5][6] However, cost, safety, and pollution concerns restrict their application scales and areas, especially in many stationary energy storages. [7][8][9][10] In comparison, multivalent metal-ion batteries using aqueous electrolytes are intrinsically safe and low cost. Specially, their multielectron transfer reactions and high ionic conductivity make them attractive and competitive.…”

Sustainable carbon coated ZrO2 electrodes with high capacitance retention for energy storage devices

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