A Durable Lithium-Tellurium Battery: Effects Of Carbon Pore Structure And Tellurium Content

Lithium-tellurium (Li-Te) batteries have attracted increasing attention as a next-generation energy storage system due to the appealing electrical conductivity and volumetric capacity. Porous carbon hosts are widely used for Te confinement to achieve good electrochemical performance in Li-Te batteries. However, there is a lack of understanding of the effect of carbon pore structure on the performance of Te/C cathodes. Herein, two types of carbons, one with micropores (ASAC25) and the other with mixed micropores and mesopores (ASAC30) are selected as Te hosts to clarify the role of carbon pore structure. Detailed investigations reveal that micropores, rather than mesopores, are critical for effective Te confinement due to complete infiltration of Te in micropores and enhanced Te and C interaction, thus enabling superior stability in ASAC25-Te. The dramatic capacity decline of ASAC30-Te is caused by the dissolution of bulky Te and the loss of active materials in long cycles. ASAC25-Te also achieved exceptional capacity retention of 83.3% after 500 cycles at 1C. Moreover, this work found that the ASAC25 carbon host should be partially filled with Te up to similar to 60 wt% to accommodate volume change of Te. The clarification is expected to provide guidance on the further development of high-energy-density Tebased rechargeable batteries. (c) 2020 Elsevier Ltd. All rights reserved.