Designing polysulfides adsorption‐conversion on g‐C3N4‐based separator via doping heteroatoms boron and phosphorus toward high‐performance lithium‐sulfur batteries

作者：Sun Yajie; Huang Wenzhi; Li Junhao; Pan Jiajie; Nan Haoxiong; Dong Huafeng; Shi Kaixiang; Liu Quanbing

来源：AIChE Journal, 2022, 69(1).

• adsorption energy
• DFT calculation
• doping P/B
• g‐C3N4 separator
• lithium‐sulfur batteries

The notorious “shuttle effect” of lithium polysulfides (LiPSs) has suppressed the large‐scale commercial application of lithium‐sulfur batteries (LSBs). Also, the intrinsic advantages including inhibiting the shuttling‐circulation and promoting the conversion of LiPSs, on the separator are deemed as stimulating blocks on the exploitation of LSBs. Herein, guided by theoretical calculations, we have designed doping‐heteroatoms boron (B) and phosphorus (P) on graphitic carbon nitride (g‐C3N4), to suppress the “shuttle effect” of LiPSs and improve the battery cycling performance. Theoretical calculations show strong chemical bonding between Li atom and N substance of g‐C3N4, and corroborates synergistic mechanism of electron transfer and van der Waals interaction. The high adsorption energies with doping B/P atoms enable LiPSs adsorption on the separators inhibiting shuttle loss. As expected, the experiment data also demonstrate that superior electrochemical performance are achieved by utilizing B‐doped g‐C3N4 (BCN) separator. Incorporating the B‐doped g–C3N4 (BCN) separator in LSBs delivered an initial specific capacity of 1050?mAh?g?1 at 1?C and 920?mAh?g?1 at 2?C. Notably, it achieved a decay rate of 0.08% and 0.1% at 1 and 2?C, respectively, after 500 cycles. This study furthers our understanding of B/P doping separator enhancement and restraining LiPSs shuttling loss for an improved LSBs performance.

• 出版日期2022