Interpenetrating gel-enabled uniform integration of metal and carbon dual matrices with nanoporous silicon for high-performance lithium storage

Abstract

The uniform incorporation of metal and carbon with nanoporous silicon is highly desirable for improving overall Li-storage performance, yet remains a great challenge owing to different physicochemical properties of Si,...

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“…Moreover, the co-incorporation of metal and carbon components could achieve synergistic lithium-storage effects toward silicon from M/C dual matrices, and thus, Si/M/C ternary anodes are able to manifest desirable overall electrochemical performance. 17–27…”

“…Up to now, various M/C components have been adopted to hybridize with silicon, including Sn/C, 17,18 Fe/C, 19,20 Co/C, 21,22 Cu/C, 23,24 and Mn/C 25 ones. In these ternary composites, M/C dual components serve as buffering/conducting matrices, boosting the structural stability and charge-transport capability of the Si/M/C anodes.…”

“…In these ternary composites, M/C dual components serve as buffering/conducting matrices, boosting the structural stability and charge-transport capability of the Si/M/C anodes. 17–27 Moreover, transition metals inhibit the undesirable amorphous-Li x Si/crystalline-Li 15 Si 4 phase transition, 8–10 whereas carbon prevents the silicon/electrolyte contact and thus stabilizes the electrode/electrolyte interface. 14 As a result, these Si/M/C ternary anodes manifest enhanced cycling stability and rate capability compared with Si/M and Si/C counterparts.…”

“…As expected, with increased scan rate, the cathode peaks of the Si/FeCo/G and Si/G anodes shift to lower potentials, whereas the corresponding anode peaks move towards higher potentials owing to the increasing polarization. 17,22 The peak current ( I p ) manifests a linear relationship with the square root of the scan rate ( v 1/2 ), suggesting a typical diffusion-controlled process. 17,22 And, the chemical diffusion coefficient could be determined by the Randles–Sevcik equation: I p = 2.69 × 10 5 n 3/2 A C 0 D 1/2 v 1/2 , where n is charge-transfer number, A means electrode surface area, C 0 corresponds to concentration, and D refers to Li + diffusion coefficient.…”

“…17,22 The peak current ( I p ) manifests a linear relationship with the square root of the scan rate ( v 1/2 ), suggesting a typical diffusion-controlled process. 17,22 And, the chemical diffusion coefficient could be determined by the Randles–Sevcik equation: I p = 2.69 × 10 5 n 3/2 A C 0 D 1/2 v 1/2 , where n is charge-transfer number, A means electrode surface area, C 0 corresponds to concentration, and D refers to Li + diffusion coefficient. Due to the similar alloying-type lithium storage mechanism, the values of parameters ( n , A , and C 0 ) are consistent for these two anodes, and the proportion of Li + diffusion coefficient is proportional to the ratio of the square of slopes ( K ).…”