Expanding pore sizes of ZIF-8-derived nitrogen-doped microporous carbon via C₆₀ embedding: toward improved anode...

Porous carbon and nanocarbons have been extensively applied as anode materials for high-energy density lithium-ion batteries (LIBs). However, as another representative nanocarbon, fullerenes, such as C₆₀, have been scarcely utilized in LIBs because of their poor electrochemical reversibility. Herein, we designed a novel C₆₀-embedded nitrogen-doped microporous carbon material (denoted as C₆₀@N-MPC), which was derived from a zeolitic imidazolate framework-8 (ZIF-8) precursor, demonstrating its promising application as a superior anode material for LIB. We first embedded C₆₀in situ into a ZIF-8 matrix via a facile solid-state mechanochemical route, which acted as a precursor and was transformed to C₆₀@N-MPC after carbonization. The C₆₀@N-MPC was applied as a novel anode for LIBs, showing an improved reversible specific capacity of ≈1351 mA h g^-1 at 0.1 A g^-1 and a better rate capacity (≈1077 mA h g^-1 at 1 A g^-1 after 400 cycles) relative to those based on the unmodified N-MPC anode. The role of C₆₀ in the superior lithium storage performance of C₆₀@N-MPC was elucidated, revealing that C₆₀ functioned as a pore expander for N-MPC with 3-20 nm mesopores (versus sub-1 nm micropores for the unmodified N-MPC), which facilitated the rapid diffusion of the organic electrolyte.