The demand for lithium-ion batteries (LIBs) with high mass-specific capacities, high rate capabilities and long-term cyclabilities is driving the research and development of LIBs with nickel-rich NMC (LiNi_xMn_yCo_1−x−yO₂, $$x \geqslant 0.5$$x⩾0.5 ) cathodes and graphite (Li_xC₆) anodes. Based on this, this review will summarize recently reported and widely recognized studies of the degradation mechanisms of Ni-rich NMC cathodes and graphite anodes. And with a broad collection of proposed mechanisms on both atomic and micrometer scales, this review can supplement previous degradation studies of Ni-rich NMC batteries. In addition, this review will categorize advanced mitigation strategies for both electrodes based on different modifications in which Ni-rich NMC cathode improvement strategies involve dopants, gradient layers, surface coatings, carbon matrixes and advanced synthesis methods, whereas graphite anode improvement strategies involve surface coatings, charge/discharge protocols and electrolyte volume estimations. Electrolyte components that can facilitate the stabilization of anodic solid electrolyte interfaces are also reviewed, and trade-offs between modification techniques as well as controversies are discussed for a deeper understanding of the mitigation strategies of Ni-rich NMC/graphite LIBs. Furthermore, this review will present various physical and electrochemical diagnostic tools that are vital in the elucidation of degradation mechanisms during operation to supplement future degradation studies. Finally, this review will summarize current research focuses and propose future research directions. Graphic The demand for lithium-ion batteries (LIBs) with high mass specific capacities, high rate capabilities and longterm cyclabilities is driving the research and development of LIBs with nickel-rich NMC (LiNi_xMn_yCo_1−x−yO₂, x ≥ 0.5) cathodes and graphite (Li_xC₆) anodes. Based on this, this review will summarize recently reported and widely recognized studies of the degradation mechanisms of Ni-rich NMC cathodes and graphite anodes. And with a broad collection of proposed mechanisms on both atomic and micrometer scales, this review can supplement previous degradation studies of Ni-rich NMC batteries. In addition, this review will categorize advanced mitigation strategies for both electrodes based on different modifications in which Ni-rich NMC cathode improvement strategies involve dopants, gradient layers, surface coatings, carbon matrixes and advanced synthesis methods, whereas graphite anode improvement strategies involve surface coatings, charge/discharge protocols and electrolyte volume estimations. Electrolyte components that can facilitate the stabilization of anodic solid-electrolyte interfaces (SEIs) are also reviewed and tradeoffs between modification techniques as well as controversies are discussed for a deeper understanding of the mitigation strategies of Ni-rich NMC/graphite LIBs. Furthermore, this review will present various physical and electrochemical diagnostic tools that are vital in the elucidation of degradation mechanisms during operation to supplement future degradation studies. Finally, this review will summarize current research focuses and propose future research directions.

Polypyrrole (PPy) nanofibers and composites, containing PPy and multiwalled carbon nanotubes (MWCNTs), were used for the fabrication of electrodes of electrochemical supercapacitors (ES). It was found that cationic malachite green (MG) dye adsorbed on PPy and MWCNTs and allowed their efficient electrosteric dispersion in water. Sedimentation tests, electrophoretic deposition (EPD) experiments, Fourier transform infrared spectroscopy and UV-Vis spectroscopy data showed strong adsorption of MG on PPy and MWCNTs. The important finding was the possibility of efficient dispersion of PPy and MWCNTs using MG dye as a co-dispersant. The new approach allowed colloidal processing of individual materials and composites. This method is suitable for the cathodic EPD of electrically neutral PPy and MWCNTs. The ES electrodes with high material loading in the range of 10–30 mg cm⁻² were prepared from colloidal suspensions of PPy nanofibers and MWCNTs using Ni foam current collectors. The composite PPy–MWCNT electrodes, prepared using MG, showed superior electrochemical performance compared to pure PPy and composite electrodes prepared without MG. The composite PPy–MWCNT electrodes with high mass loadings showed excellent capacitance retention at high scan rates and over a wide range of frequencies, and excellent cycling stability. The highest capacitance of 4.62 F cm⁻² was obtained at a material loading of 30 mg cm⁻². The PPy nanofiber–MWCNT composites, prepared using MG as a dispersant, are promising electrodes for ES.