High‐Rate Lithium–Selenium Batteries Boosted by a Multifunctional Janus Separator Over a Wide Temperature Range of −30 °C to 60 °C

• Published in: Advanced materials (Weinheim) 2023-11, Vol.35 (46), p.e2304551-n/a
• Main Authors: Guo, Yue, Zhu, Shengqing, Mao, Chenghui, Chen, Yiqun, Liu, Liwei, Liu, Jiaheng, Wang, Xizhang, Wu, Qiang, Yang, Lijun, Hu, Zheng
• Format: Article
• Language: English
• Subjects: Chemisorption; Electrical resistivity; electrocatalysis; Extreme environments; Janus separator; Lithium; lithium dendrites; Lithium sulfur batteries; lithium–selenium batteries; Materials science; Nanowires; Room temperature; Selenium; Separators; shuttling effect
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202304551

Lithium–selenium batteries are characterized by high volumetric capacity comparable to Li–S batteries, while ≈1025 times higher electrical conductivity of Se than S is favorable for high‐rate capability. However, they also suffer from the “shuttling effect” of lithium polyselenides (LPSes) and Li dendrite growth. Herein, a multifunctional Janus separator is designed by coating hierarchical nitrogen‐doped carbon nanocages (hNCNC) and AlN nanowires on two sides of commercial polypropylene (PP) separator to overcome these hindrances. At room temperature, the Li–Se batteries with the Janus separator exhibit an unprecedented high‐rate capability (331 mAh g−1 at 25 C) and retain a high capacity of 408 mAh g−1 at 3 C after 500 cycles. Moreover, the high retained capacities are achieved over a wide temperature range from −30 °C to 60 °C, showing the potential application under extreme environments. The excellent performances result from the “1+1>2” synergism of suppressed LPSes shuttling by chemisorption and electrocatalysis of hNCNC on the cathode side and suppressed Li‐dendrite growth by thermally conductive AlN‐network on the anode side, which can be well understood by the “Bucket Effect”. This Janus separator provides a general strategy to develop high‐performance lithium–chalcogen (Se, S, SeS2) batteries. A Janus separator coated by hierarchical nitrogen‐doped carbon nanocages (hNCNC) and AlN nanowires on polypropylene separator is constructed to achieve high‐rate performances of Li–Se batteries over −30–60 °C. The excellent performances result from “1+1>2” synergism of suppressed ‘shuttling effect’ by hNCNC on cathode side and suppressed Li‐dendrites by AlN‐network on anode side, well understood by the “Bucket Effect”.