Li‐Ion Battery Anodes Combining Intercalation and Plating Energy Storage Mechanisms through SiOx/C Coated Graphite

Abstract

ABSTRACT Anode‐less batteries are one of the most promising technologies to increase the energy density of lithium‐ion batteries (LIBs). However, compared to conventional LIBs with graphite anodes, they tend to degrade much faster. To balance energy density and lifetime, we propose a hybrid anode where part of the energy is stored by the lithiation of graphite and part by plating Li on graphite. Without special measures, the latter leads to accelerated capacity loss, which we address here by coating the graphite with a thin lithiophilic SiO x /C layer using a scalable sol‐gel process. By tuning the thickness of the SiO x /C layer and modifying a localized high concentration electrolyte, we simultaneously achieve reversible Li plating/stripping and high‐capacity contribution from graphite intercalation with a considerable Li plating contribution (1/3). Overall, this results in hybrid anodes with a specific capacity of 584 mAh g −1 and capacity retention of 86% over 500 cycles in a full cell versus NMC532 with an N/P ratio of 0.67. This far exceeds the 372 mAh/g theoretical capacity of graphite while at the same time doubling the lifetime compared to the best anode‐less batteries reported to far.