Lithium-ion battery is a type of rechargeable batteries as a major energy storage device. One of the most notable topics is to develop high performance Li-ion battery anode materials. Current commercial anodes are made of graphite-based materials, that only has a specific capacity of 372 mAh g-1. Scientists are now looking for various candidates with higher capacity and longer endurance life. One of them is Sn-carbon composite. Sn or SnO2 can be a potential anode with high capacity, but there’re still various challenges, such as the Li2O phase formation and volume expansion of the Sn phase constitute the main barriers that have to be overcome.
To solve the drawbacks, cobalt as well as urea are introduced. The introduction of urea changes the pH of the solution in the hydrothermal process. Urea gives better dispersion of nano-sized SnO2 on the Graphene Oxide Sheets. The minimal grain size of SnO2 is obtained at pH 4.1 with the amount of urea 1 gram. The increase of reduction temperature makes the weight percent of carbon in the sample decrease. SnO2 is totally reduced to pure Sn for all samples at 650 oC. The complete reduction to Sn from SnO2 is preferred because Sn formation reduces the first cycle irreversibility.
By adding cobalt, SnO2 is fully reduced to Sn all the samples with 8 different atomic percentage of Co to Sn at 550 oC. Cobalt makes the better nucleation of Sn nanoparticles on Graphene Oxide Sheets and restricts the growth of Sn particle size. RGO-1-Sn-1-Co/C-H synthesized by two-step method (1% atomic percentage of Co to Sn) gives the best performance among the others because it gives the minimum Sn particle size and also the highest Sn weight percent. This material can be a candidate for an advanced anode material with high 1st columbic efficiency (74.2%), high capacity at 30th cycle (635.7 mAh/g at 200 mA/g current density), and also good capacity retention.

Lithium-ion battery is a type of rechargeable batteries as a major energy storage device. One of the most notable topics is to develop high performance Li-ion battery anode materials. Current commercial anodes are made of graphite-based materials, that only has a specific capacity of 372 mAh g-1. Scientists are now looking for various candidates with higher capacity and longer endurance life. One of them is Sn-carbon composite. Sn or SnO2 can be a potential anode with high capacity, but there’re still various challenges, such as the Li2O phase formation and volume expansion of the Sn phase constitute the main barriers that have to be overcome.
To solve the drawbacks, cobalt as well as urea are introduced. The introduction of urea changes the pH of the solution in the hydrothermal process. Urea gives better dispersion of nano-sized SnO2 on the Graphene Oxide Sheets. The minimal grain size of SnO2 is obtained at pH 4.1 with the amount of urea 1 gram. The increase of reduction temperature makes the weight percent of carbon in the sample decrease. SnO2 is totally reduced to pure Sn for all samples at 650 oC. The complete reduction to Sn from SnO2 is preferred because Sn formation reduces the first cycle irreversibility.
By adding cobalt, SnO2 is fully reduced to Sn all the samples with 8 different atomic percentage of Co to Sn at 550 oC. Cobalt makes the better nucleation of Sn nanoparticles on Graphene Oxide Sheets and restricts the growth of Sn particle size. RGO-1-Sn-1-Co/C-H synthesized by two-step method (1% atomic percentage of Co to Sn) gives the best performance among the others because it gives the minimum Sn particle size and also the highest Sn weight percent. This material can be a candidate for an advanced anode material with high 1st columbic efficiency (74.2%), high capacity at 30th cycle (635.7 mAh/g at 200 mA/g current density), and also good capacity retention.

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