Super High Capacity of Lithium Battery Silicon–Carbon Anode over 6,500 mAh g−1

TL;DR

Silicon-carbon composites in lithium batteries show record-breaking capacity, potentially revolutionizing battery energy storage.

Contribution

Silicon–carbon composites exceed silicon's theoretical capacity using internal defects and AI-assisted optimization.

Findings

Silicon–carbon composites achieved 6,694.21 mAh g−1 initial discharge capacity at 0.1 C.

Optimized electrolyte increased Coulombic efficiency to 90.96% with 5,294.88 mAh g−1 capacity.

AI model predicts a theoretical maximum capacity of 7,789.55 mAh g−1 for these composites.

Abstract

As silicon anodes approach their theoretical capacity limits in lithium-ion batteries, the exploration of materials with even higher energy storage potential becomes imperative. Here, we demonstrate that silicon–carbon composites can deliver ultrahigh capacities exceeding 6,500 mAh g−1, benefiting from the abundant internal defects within the composite. At a charge–discharge rate of 0.1 C (0.42 A g−1), the initial discharge specific capacity reaches 6,694.21 mAh g−1, with a Coulombic efficiency (CE) of 74.71%, markedly exceeding the theoretical capacity limit of silicon. By further optimizing lithium battery electrolyte, the initial discharge specific capacity is 5,294.88 mAh g−1 and CE is increased to 90.96%. Moreover, an artificial intelligence-assisted framework combining a multilayer perceptron with a constrained genetic algorithm predicts a theoretical maximum initial discharge capacity of 7,789.55 mAh g−1. These results provide compelling evidence that silicon–carbon composites hold great promise for substantially enhancing the energy density of next-generation lithium-ion batteries.

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