Extremely Durable K-Ion Batteries Enabled by Heteroatom Co-Doped Highly-Ordered Porous Carbon Spheres with Nearly 100% Capacity Retention up to 11,000 Cycles.

Fu, Yanqing; Shen, Xiang; You, Juan; Yu, Ruizhi; Zheng, Jinju; Wu, Bing; Sofěr, Zdenek; Wei, Qiliang et al. · Nano Lett · 2024

basic_science · Level V

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Abstract

Currently, one major target for exploring K-ion batteries (KIBs) is enhancing their cycle stability due to the intrinsically sluggish kinetics of large-radius K<sup>+</sup> ions. Herein, we report a rationally designed electrode, the S/O co-doped hard carbon spheres with highly ordered porous characteristics (SPC), for extremely durable KIBs. Experimental results and theory calculations confirm that this structure offers exceptional advantages for high-performance KIBs, facilitating rapid K<sup>+</sup> diffusion and (de)-intercalation, efficient electrolyte penetration and transport, improved K<sup>+</sup> storage sites, and enhanced redox reaction kinetics, thus ensuring the long-term cycle stability. As a result, the as-constructed SPC anode delivers a high reversible capacity of ca. 200 mAh g<sup>-1</sup> at a high current density of 2.0 A g<sup>-1</sup> and robust stability with ∼100% capacity retention up to 11,000 cycles, outperforming most carbon-based KIB anodes. This work offers insight into developing advanced KIBs with durable stability toward practical applications.