Uniform Deposition and Effective Confinement of Lithium in Three-Dimensional Interconnected Microchannels for Stable...

Lithium dendrite formation has hindered the practical implementation of lithium metal batteries with higher energy densities compared with those of conventional lithium-ion batteries. Herein, a nanoconfinement strategy to access dendrite-free lithium metal anodes comprising three-dimensional (3D) hollow porous multi-nanochannel carbon fiber embedded with TiO₂ nanocrystals (HTCNF) is reported. The transport of the lithium ions is facilitated by the 3D architecture. Functioning as nanoseeds, the TiO₂ nanocrystals guide the lithium ions toward forming uniform deposits, which are further confined inside the hollow carbon fibers and the 3D HTCNF layer. Site-selective deposition coupled with the nanoconfinement of lithium metal modifies the Li plating/stripping behavior and effectively suppresses the dendrite growth. The HTCNF-Li cell delivers a stable cycling performance of 1300 h with a voltage hysteresis as low as 6 mV. The assembled HTCNF-Li//LiFePO₄ full cell displays a compelling rate performance and enhanced cycling stability with high capacity retention (90% after 400 cycles at 0.5 C). Our results demonstrate a new and potentially scalable route to resolve the lithium dendrite growth issue for enhanced electrochemical performances, which can be further extended to other metal battery systems.