Li+-intercalated carbon cloth for anode-free Li-ion batteries with unprecedented cyclability

Abstract

Anode-free Li-ion batteries (AFLIBs) are regarded as among the most promising Li-based batteries for quantum leaps in energy densities. However, despite extensive efforts, the performance of AFLIBs is still in its infancy, requiring striking improvement, particularly in cycle stability. This study shows for the first time that carbon cloth (CC) can embody viable AFLIBs with unprecedented cyclability. In contrast to other carbonaceous substrates, CC with a cross-aligned weave pattern enables the immediate formation of a thin, uniform solid-electrolyte-interface (SEI) layer, which is robust during subsequent charge/discharge cycles. Li plating/stripping through stable SEI layers is also nearly perfectly reversible with no sign of dendrites owing to the increased Li⁺ flux and facilitated nucleation on CC. Consequently, when SEI-formed CC (i.e., CC in a reduced state with Li⁺ ions inserted) is coupled with LiFePO₄ in conventional carbonate electrolytes, Li⁺ ions released from LiFePO₄ are not consumed by side reactions, Li⁺ ions inserted in SEI-formed CC remain intact, and AFLIBs exhibit unprecedented long-term cyclability with no short circuit. The capacity retention amounts to 91.00% for 3000 charge/discharge cycles with an average coulombic efficiency of 99.94%, which is incomparably high compared to the best performance of AFLIBs reported to date (80% after 195 cycles). The results of the study are expected to provide an innovative idea for the development of commercial AFLIBs.