A broad pore size distribution mesoporous SnO _2 as anode for lithium-ion batteries

摘要

We demonstrate here that mesoporous tin dioxide (abbreviated M-SnO _2) with a broad pore size distribution can be a prospective anode in lithium-ion batteries. M-SnO _2 with pore size ranging between 2 and 7.5 nm was synthesized using a hydrothermal procedure involving two different surfactants of slightly different sizes, and characterized. The irreversible capacity loss that occurs during the first discharge and charge cycle is 890 mAh g ~(-1), which is smaller than the 1,010-mAh g ~(-1) loss recorded for mesoporous SnO _2 (abbreviated S-SnO _2) synthesized using a single surfactant. After 50 cycles, the discharge capacity of M-SnO _2 (504 mAh g ~(-1)) is higher than that of S-SnO _2 (401 mAh g ~(-1)) and solid nanoparticles of SnO 2 (abbreviated nano-SnO _2<4 mAh g ~(-1)) and nano-SnO _2. Transmission electron microscopy revealed higher disorder in the pore arrangement in M-SnO _2. This, in turn imparts lower stiffness to M-SnO _2 (elastic modulus, E R≈14.5 GPa) vis-a-vis S-SnO _2 (E _R≈20.5 GPa), as obtained using the nanoindenta-tion technique. Thus, the superior battery performance of M-SnO _2 is attributed to its intrinsic material mechanical property. The fluidity of the internal microstructure of M-SnO _2 resulted in a lower degree of aggregation of Sn particles compared to S-SnO _2 and nano-SnO _2 structural stabilization and long-term cyclability.