Porous Bamboo‐Derived Carbon as Selenium Host for Advanced Lithium/Sodium–Selenium Batteries

Abstract

Selenium (Se) has received extensive attention as the most competitive cathode material for next generation high‐energy batteries. However, the shuttle effect of polyselenide and volume change lead to inferior electrochemical properties. To solve these issues, a porous bamboo‐derived carbon (PBC) with abundant meso/micropores is prepared as a framework to effectively encapsulate elemental selenium. For Li–Se batteries, Se/PBC electrode delivers an outstanding capacity of 509 mAh g−1 after 200 cycles at 0.2 C (1 C = 675 mA g−1) with a low capacity fade of 0.036% per cycle. The Se/PBC composite also reveals a satisfied electrochemical performance for Na–Se batteries with an excellent capacity of 409 mAh g−1 after 200 cycles at 0.2 C. Moreover, Se/PBC electrode also presents excellent long‐term cycle performance and rate performance at 15 C for Li–Se batteries and 10 C for Na–Se batteries. The outstanding properties are attributed to the specific 3D structure and high conductivity of PBC, which significantly inhibits the shuttle effect and enhances the reaction kinetics. Herein, not only the great application potential of bamboo in energy storage systems is demonstrated, but also an effective approach and low‐cost strategy for improving the performance of lithium/sodium–selenium batteries is offered.

Synergy of MXene with Se Infiltrated Porous N‐Doped Carbon Nanofibers as Janus Electrodes for High‐Performance Sodium/Lithium–Selenium Batteries

“…The admirable long-term cycling performance of PNCNFs/Se@MXene electrodes at high current densities is superior compared to previously reported cathode materials in Na-Se batteries (Table S2, Supporting Information). [1,12,15,16,18,[35][36][37][38][41][42][43][44][45] To further understand the electrochemical characteristics of NCNFs/Se, PNCNFs/Se, and PNCNFs/Se@MXene in Na-Se batteries, the electrochemical kinetics was studied via CV measurements in the scanning rate range of 0.1-0.5 mV s −1 . As shown in Figure 4a, there are two characteristic peaks (denoted as Peak O and Peak R).…”

Amorphous Se Restrained by Biomass-Derived Defective Carbon for Stable Na–Se Batteries

“…According to the N 2 adsorption/desorption isotherms and pore-size distribution, as shown in Figure S6, the surface area of the NOPCC decreased from 468.3 to 40.2 m 2 g −1 along with a sharp reduction of the pore-size distribution after the selenation, suggesting that the pores of NOPCC are occupied by Se. 39,40 The large specific surface area and abundant pores of NOPCC not only relieve the mechanical stress caused by sodiation but also restrict the amorphous Se molecules in the inner pores. In addition, the interaction between Se and the carbon matrix was also revealed using DFT calculations, as shown in Figure 2f.…”

A Facile Pre-Lithiated Strategy towards High-Performance Li2Se-LiTiO2 Composite Cathode for Li-Se Batteries

“…In the subsequent charging process, a long plateau at ~2.18 V is observed, which is related to the reversible conversion of Li 2 Se 2 /Li 2 Se to Li 2 Se n (8 ≥ n ≥ 4) and Se [ 46 , 47 ]. Meanwhile, during the discharge process, the Li 2 Se, Li 2 Se-LiTiO 2 and Li 2 Se-TiO 2 cathodes have two voltage plateaus located at ~2.12 V and ~2.05 V, respectively, which are ascribed to the multistep phase transitions of Se to soluble long-chain Li 2 Se n (8 ≥ n ≥ 4) and further to insoluble short-chain Li 2 Se 2 /Li 2 Se [ 48 , 49 ]. It is worth noting that when the first charging voltage is 2.6 V, Li 2 Se is nonactivated and the Li + is not completely detached from Li 2 Se, exhibiting terrible cycling performance ( Figure S4 ).…”