Highly reversible and rapid charge transfer Zn-MnO2 battery by MnO2 nanosheet arrays anchored nanocellulose-based carbon aerogel

Zn-MnO2 batteries are eco-friendly energy storage devices, but their practical application is hindered by challenges such as low conductivity, sluggish Zn2+ diffusion kinetics, and instability in the crystal structure of manganese dioxide (MnO2) cathode materials during Zn2+ insertion/extraction. In this work, a composite nanocellulose-based carbon aerogel@MnO2 (CA@MnO2) cathode with enhanced Zn2+ insertion/de-insertion kinetics and storage capacity was fabricated by bi-directional freezing, carbonization, and following hydrothermal deposition. The nanocellulose-based carbon aerogels with ordered porous structure and high specific surface area served as the substrate, which facilitated the rapid Zn2+ migration and efficient electrode contact interface. In the two-electrode system, the CA@MnO2 can provide a reversible specific capacity of 480 mAh g−1 at 0.5 A g−1 and a high multiplicative capacity of 160 mAh g−1 at 5 A g−1 with outstanding stability of operation over 3000 cycles. The assembled Zn//CA@MnO2 batteries attained a remarkable specific capacitance of 397 mAh g−1 at a current density of 0.1 A g−1. This study provides a feasible route for the preparation of high-performance Zn-ion batteries.