Deep Cycling for High-Capacity Li-Ion Batteries.

As the practical capacity of conventional Li-ion batteries (LIBs) approaches the theoretical limit, which is determined by the rocking-chair cycling architecture, a new cycling architecture with higher capacity is highly demanded for future development and electronic applications. Here, a deep-cycling architecture intrinsically with a higher theoretical capacity limit than conventional rocking-chair cycling architecture is developed, by introducing a follow-up cycling process to contribute more capacity. The deep-cycling architecture makes full use of movable ions in both of the electrolyte and electrodes for energy storage, rather than in either the electrolyte or the electrodes. Taking LiMn2 O4 -mesocarbon microbeads (MCMB)/Li cells as a proof-of-concept, 57.7% more capacity is obtained. Moreover, the capacity retention is as high as 84.4% after 2000 charging/discharging cycles. The deep-cycling architecture offers opportunities to break the theoretical capacity limit of conventional LIBs and makes high demands for new-type of cathode materials, which will promote the development of next-generation energy storage devices.