Hierarchical N-doped porous carbon hosts for stabilizing tellurium in promoting Al-Te batteries

Aluminum batteries are attractive in electrochemical energy storage due to high energy density and lowcost aluminum, while the energy density is limited for the lack of favorable positive electrode materials to match aluminum negative electrodes. Tellurium positive electrode is intrinsically electrically conductive among chalcogen and holds high theoretical specific capacity (1260.27 mAh g(-1)) and discharge voltage plateau (-1.5 V). However, the chemical and electrochemical dissolution of Te active materials results in the low material utilization and poor cycling stability. To enhance the electrochemical performance, herein a nitrogen doped porous carbon (N-PC) is derived from zeolite imidazolate framework (ZIF-67) as an effective tellurium host to suppress the undesired shuttle effect. In order to inhibit the volume expansion of N-PC during the charge/discharge process, the reduced graphene oxide (rGO) nanosheets are introduced to form a stable host materials (N-PC-rGO) for stabilizing Te. The physical encapsulation and chemical confinement to soluble tellurium species are achieved. N-PC-rGO-Te positive electrode exhibits an improved initial specific capacity and long-term cycling performance at a current density of 500 mA g(-1) (initial specific capacity: 935.5 mAh g(-1); after 150 cycles: 467.5 mAh g(-1)), highlighting a promising design strategy for inhibiting chemical and electrochemical dissolution of Te. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

In order to improve the electrochemical performance of aluminum batteries, a nitrogen-doped porous carbon (N-PC) derived from zeolite imidazolate framework (ZIF-67) is used as an effective host for tellurium to suppress the undesirable shuttle effect. The introduction of reduced graphene oxide (rGO) nanosheets helps to stabilize tellurium by inhibiting the volume expansion of N-PC during charge/discharge cycles, achieving physical encapsulation and chemical confinement of soluble tellurium species. The N-PC-rGO-Te positive electrode demonstrates improved initial specific capacity and long-term cycling performance, showcasing a promising design strategy for inhibiting the chemical and electrochemical dissolution of tellurium in aluminum batteries.