Biochar‐Derived Hierarchical Porous Carbon as Tellurium Host for High‐Performance Potassium‐Tellurium Batteries

Abstract

Potassium ion battery is promising for its high abundance and low redox potential. As a conversion cathode, Te possesses high conductivity and theoretical volumetric capacity to couple with potassium. The stubborn issues of K‐Te battery focus on the large volume change and rapid structure degradation of Te. Herein, we produce biomass carbon from mangosteen shell in a facile method, and obtain a hierarchical porous host with abundance of micropores and mesopores, which is beneficial for hosting Te during K+ storage in K‐Te battery obviously. The specific capacity reach to 560 mAh g‐1 in the initial cycle at 0.1 A g‐1, and remained 83.8% after 200 cycles. Impressively, at a high current density of 2.0 A g‐1, the specific capacity still remained 62.6% after 5000 cycle. These results endow such strategy an efficient way for the development of K‐Te batteries.

Tellurium and Nano-Tellurium: Medicine or Poison?

“…This alloy possesses large absorption coefficients in the visible light region as stable, eco-friendly and high-efficiency light absorbers used in optoelectronic applications [68] Rubidium-tin-tellurium alloy Rb 2 Sn 1−x Te x I 6 Promising alloy using the Sn-Te mixture as a potential substitute for lead in photovoltaic materials [69] Tellurium-embedded carbon nano-fibers Te@C-NF electrode Poly-tellurides and K 2 Te-embedded carbon nano-fibers are high-rate and long-life electrodes for high-energy-storage materials [70] Potassium-tellurium battery system K-Te Converting Te to K 2 Te 3 and ultimately to K 5 Te 3 in a carbonate electrolyte-based K-Te battery system to promote and develop high-energy-density K-S/Se/Te batteries [71] Potassium-tellurium battery system K-Te Utilizes biochar from mangosteen shell in a hierarchical porous host to Te during K + storage in K-Te battery [72] Amorphous selenium (a-Se)-tellurium alloy Se-Te alloys Improving quantum efficiency and conversion efficiencies for a-Se 1−x Te x (x = 0, 0.03, 0.05, 0.08) devices as a function of applied field, along with different band gaps in Se-Te alloys [73] Bulk-Te compounds are relatively limited in their applications due to Te's high toxicity, whereas nano-Te forms have shown promising applications in the pharmaceutical and biomedical fields (Figure 4). Their biomedical applications may include their antimicrobial [12], antifungal [74], antibacterial [75], and anticancer [76] activities, their use as therapeutic agents [77], and their use in imaging applications [17,38,78].…”