Optimization of Porous Structures of Carbon Matrices for Loading Red Phosphorus to Achieve High-Capacity and Long-Life Anodes for All-Solid-State Lithium-Ion Batteries.

Abstract

All-solid-state lithium-ion batteries (ASSLIBs) using sulfide electrolytes and high-capacity alloy-type anodes have attracted sizable interest due to their potential excellent safety and high energy density. Encapsulating insulating red phosphorus (P) inside nanopores of a carbon matrix can adequately activate its electrochemical alloying reaction with lithium. Therefore, the porosity of the carbon matrix plays a crucial role in the electrochemical performance of the resulting red P/carbon composites. Here, we use zeolite-templated carbon (ZTC) with monodisperse micropores and mesoporous carbon (CMK-3) with uniform mesopores as the model hosts of red P. Our results reveal that micropores enable more effective pore utilization for the red P loading, and the P@ZTC material can achieve a record-high content (65.0 wt %) of red P confined within pores. When used as an anode of ASSLIBs, the P@ZTC electrode delivers an ultrahigh capacity of 1823 mA h g-1 and a high initial Coulombic efficiency of 87.44%. After 400 deep discharge-charge cycles (running over 250 days) at 0.2 A g-1, the P@ZTC electrode still holds a reversible capacity of 1260 mA h g-1 (99.92% capacity retention per cycle). Moreover, a P@ZTC||LiNi0.8Co0.1Mn0.1O2 full cell can deliver a reversible areal capacity of over 3 mA h cm-2 at 0.1C after 100 cycles.