Enhanced lithium-ion battery performance with a novel composite anode: S-doped graphene oxide, polypyrrole, and fumed silica.

In this work, a novel composite anode material was developed, utilizing S-doped graphene oxide (SGO), polypyrrole (PPy), and fumed silica to enhance the performance of lithium-ion batteries (LIBs). The chronoamperometric approach was used to produce SGO, while the chemical method was employed to synthesize PPy. A composite of SGO, PPy, and fumed silica was prepared as an anode for a half-cell, using two samples: one with a high PPy ratio (S1) and the other with a low PPy ratio (S2) and compared the results with bare sample (S0). The S1 sample exhibited a good initial discharge capacity (648 mAh/g), with capacities of 207 and 131 mAh/g at 5C and 10C, respectively. S1 and S2 also demonstrated superior cycling stability at a high current (100 cycles at 10C), with a retention capacity of 99 and 87%, respectively compared with S0 which retained only 68%. Coin-type full cells with S1 as the anode and LiFePO4 (LFP) as the cathode were assembled and compared with commercial graphite anodes. The S1 full cell showed a high reversible capacity (164 mAh/g at 0.1C), with a capacity retention of 66% after 100 cycles at 10C. At the same time, the graphite anode exhibited a reversible capacity of 133 mAh/g at 0.1C, with a capacity retention of 58% after 100 cycles at 10C. The S1 full cell achieved a gravimetric energy density of 164 W h/kg at 0.1C and 49 W h/kg at 10C, which is 25% greater than that of the graphite full cell (39 W h/kg) at 10C. These distinguishing characteristics of S1 make it a viable substitute for graphite as a high-performance anode material in LIBs, opening the possibility for devices with reliable battery systems.