Three-dimensional graphene cross-linked carbon nanotube doping as cathode for aqueous zinc ion batteries

AbstractAqueous zinc ion batteries (ZIBs) are becoming increasingly popular in the field of energy storage due to their high safety and environmental friendliness. This study comparatively investigated the electrochemical performance of β-MnO2 as a cathode for ZIBs after doping with different ratios of three-dimensional graphene (3D-GPE)/carbon nanotube (CNT) cross-linked composite materials with ball milling. The results show that 3D-GPE/CNT cross-linked composite has an effect on β-MnO2 microstructure and particle morphology. The cathode made of β-MnO2/(3D-GPE/CNT) with a mass ratio of 9:1 has a very high reversible capacity of 1078.93 mAh/g at a current density of 10 mA g−1, which is about 2.24 and 1.87 times the other two ratio materials (18:1 and 12:1), respectively. After 100 cycles, the median voltage difference of the β-MnO2/(3D-GPE/CNT) mass ratio 9:1 specimen battery increased. The higher the median voltage, the higher the energy of the battery. The improvement of cathode performance is directly related to the micro-state, such as the three-dimensional frameworks and carbon nanotube structures of 3D-GPE/CNT, and the macro-state, such as particle refinement, homogenization, and layered structure.Keywords: 3D GPE/CNT cross-linked compositeas-milled β-MnO2 cathodeaqueous zinc ion batterycathode materialenergy storage Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by 2023 Hebei Province and Hebei University School-level Student Innovation and Entrepreneurship Training project [S202310075044 and 2023232], Ministry of Education’s "Spring Fai Project" cooperative research project [202200397], Hebei University 2022 Laboratory Opening Project [sy202266].