A three-dimensional crosslinked chitosan sulfate network binder for high-performance Li-S batteries

Poor cycling performance caused by the shuttle effect of polysulfides is the main obstacle in the development of advanced lithium-sulfur(Li-S)batteries.Functional polymer binders with polar groups can effectively adsorb polysulfides chemically,thereby suppressing the shuttle effect.Herein,a robust three-dimensional crosslinked polymer network,which demonstrates excellent mechanical property and strong affinity for polysulfides,is prepared by the aldimine condensation and coordination reactions.The crosslinked chitosan sulfate network(CCSN)significantly enhances the cycling performance and rate capability of the sulfur cathode.The CCSN-based sulfur cathode exhibits a high initial discharge capacity of 824 m Ah g^(-1) with only 0.082%average capacity loss per cycle at 1 C.At a high rate of 4 C,the cathode exhibits a high capacity retention of 84.8%after 300 cycles.Moreover,the CCSN-based sulfur cathode exhibits an excellent cycling performance at a high sulfur loading of 2.5 mg cm^(-2),which indicates the excellent mechanical strength and binding performance of the CCSN binder for high-energy density Li-S batteries.This study demonstrates a viable approach for developing high-performance Li-S batteries for practical application.

Exploring porous zeolitic imidazolate frame work-8(ZIF-8)as an efficient filler for high-performance poly(ethyleneoxide)-based solid polymer electrolytes

Nano Research volume 13,pages2259–2267(2020)Cite this article 277 Accesses 1 Altmetric Metrics details Abstract The incorporation of inorganic fillers into poly(ethyleneoxide)(PEO)-based solid polymer electrolytes(SPEs)is well known as a low-cost and effective method to improve their mechanical and electrochemical properties.Porous zeolitic imidazolate framework-8(ZIF-8)is firstly used as the filler for PEO-based SPEs in this work.Due to the introduction of ZIF-8,an ionic conductivity of 2.2×10^−5 S/cm(30℃)is achieved for the composite SPE,which is one order of magnitude higher than that of the pure PEO.ZIF-8 also accounts for the broader electrochemical stability window and lithium ion transference number(0.36 at 60℃)of the composite SPE.Moreover,the improved mechanism of ZIF-8 to the composite SPE is investigated by zeta potential and Fourier transform infrared spectrograph characterizations.The stability at the composite SPE/lithium interface is greatly enhanced.The LiFePO4||Li cells using the composite SPE exhibit high capacity and excellent cycling performance at 60℃,i.e.,85%capacity retention with 111 mA·h/g capacity retained after 350 cycles at 0.5 C.In comparison,the cells using the pure PEO show fast capacity decay to 74 mA·h/g maintaining only 68 capacity.These results indicate that the PEO-based SPEs with ZIF-8 are of great promise for the application in solid-state lithium metal batteries.