Improving Ca‐Ion Storage Dynamic and Stability by Interlayer Engineering and Mn‐Dissolution Limitation Based on Robust MnO₂@PANI Hybrid Cathode

Abstract

Rechargeable Ca‐ion batteries (CIBs) have attracted great interest due to potentially high output voltage and abundant calcium resources. Among various cathode materials, manganese oxides with high theoretical capacity and low cost are suitable as strong candidates for rechargeable CIBs. However, the dissolution of manganese and the strong electrostatic interactions between Ca2+ and host materials result in inferior cycle stability and poor rate performance. Herein, a MnO2‐polyaniline (PANI) hybrid cathode with both PANI intercalation and coating is developed to solve the above problems. The intercalation of PANI can expand the interlayer spacing and effectively buffer the local electrostatic interaction for facile Ca2+ diffusion. Meanwhile, the density functional theory (DFT) calculations prove that the PANI coating inhibits manganese dissolution by forming strong Mn‐N bonds to enhance the structural integrity of MnO2. Benefitting from the above, the MnO2‐PANI (MnO2‐P) cathode delivers high capacity (150 mAh g⁻1 at 0.1 A g⁻1), excellent rate performance (120 mAh g⁻1 at 1 A g⁻1) and long‐term cycling stability (5000 cycles). The organic‐inorganic hybrid desig provides a new strategy for developing high performance CIBs cathode materials.

Regulation of polyaniline thickness and substitution position on Cu foams to optimize hydrogen evolution and ethanol oxidation performance

“…The FT-IR spectra of PANI in the PANI/ CF-210 catalyst illustrated typical absorption bands at 825 cm −1 ascribed to aromatic ring and out-of-plane deformation vibrations, 1146 cm −1 to the CvN stretching vibrations, 1169 cm −1 to the C-H structural vibrations, 1304 cm −1 to the C-N stretching vibrations, 1500 cm −1 to the benzene ring stretching vibrations and 1591 cm −1 to the quinone ring stretching vibrations, which were characteristic absorption bands associated with PANI. [33][34][35] This indicated the successful modification of PANI on the surface of CF. The high-resolution XPS spectra of Cu 2p, N 1s, and C 1s are shown in Fig.…”