Rational design of nano-Fe₃O₄encapsulated in 3D honeycomb biochar for enhanced lithium storage performance

Developing green materials applied in lithium-ion batteries is of significant importance for the present-day society. Herein, a feasible strategy to construct Fe₃O₄nanoparticles (NPs) embedded in three-dimensional (3D) honeycomb biochar derived from pleurotus eryngii was proposed. The obtained material consists of Fe₃O₄NPs (35-85 nm) encapsulated in 3D honeycomb biochar possesses a high specific capacity of 723 mAh g^-1at 1.5 A g^-1after 1000 cycles. The effectively enhanced cycling life of Fe₃O₄@C nanocomposites can be ascribed to the small Fe₃O₄NPs provide lower degree of cracking and high specific capacity, while the honeycomb biochar function like a cage to inhibit huge volume change of Fe₃O₄NPs during the charge-discharge process.