Chaosheng Zhang,Xiwei Lan,Qing Liu,Le Yu,Yaqian Li,Xianluo Hu
LiMn 2 O 4 -based lithium-ion batteries (LIBs) have attracted considerable attention due to their cost advantage, but industrial use has been hindered by severe capacity deterioration during cycling with LiPF 6 -based carbonate electrolytes, especially under high-temperature (55 °C) cycling conditions. Herein, a bifunctional, Janus-faced, inorganic-organic hybrid separator is demonstrated to ensure long-term cycling reversibility of LiMn 2 O 4 ||graphite LIBs. The monolithic all-nanomat separator is constructed by a bottom layer of poly ( m -phenylene isophthalamide) nanofibers by electrospinning and a top layer of interpenetrating hydroxyapatite/bacterial cellulose fibers . Benefiting from such a unique Janus configuration, the as-formed separator exhibits synergistic coupling in functions, simultaneously scavenging trace acid and mitigating the dissolution/deposition of Mn 2+ ions in batteries. Consequently, the cells with the Janus separator achieve enhanced capacity retention compared with traditional cells with the commercial polyolefin separator over 100 cycles at 55 °C. Furthermore, bulk structure and surface chemistry characterizations confirm that irreversible structural change in the LiMn 2 O 4 cathode could be avoided, and the amount of manganese on the graphite anode from the cycled cells with the Janus separator is suppressed. This work demonstrates that a composite Janus all-nanomat separator offers an unexpected route towards highly durable LiMn 2 O 4 -based LIBs.
Ming Zhu,Jiaxin Wu,Wei-Hong Zhong,Jinle Lan,Gang Sui,Xiaoping Yang
Lithium (Li) dendrites in Li anodes, and dissolution and migration of manganese (Mn) ions in LiMn 2 O 4 (LMO) cathodes, have hampered these extraordinary electrode materials from being efficiently applied in high performance Li batteries. Here, a novel, bifunctional, biobased composite gel polymer electrolyte (c-GPE) is created to simultaneously deal with the two critical issues. The skeleton of c-GPE is constructed from a sandwich structure composed of porous polydopamine spheres and two layers of the environmentally friendly soy protein isolate-based nanofiber membranes, and the carbonized polydopamine spheres are coated without any binder on the surface of the membranes. After a facile and innocuous preparation process, the skeleton material displays excellent thermal stability and good affinity to liquid electrolyte, which endows c-GPE with significant functions of effective mitigation of the dissolution of Mn ions, and chelation of the fleeing Mn ions, as well as the dramatic suppression of Li dendrite growth. Consequently, the LMO/Li batteries involving c-GPE show a great improvement in the cycling stability and rate performance compared with those of the cells based on commercial Celgard 2400. This work will be quite promising to meet the distinct requirements from Li batteries and provide a high-efficiency and safe biobased GPE for next generation energy storage systems.
危险品化学品经营许可证（带存储）