Investigation Of Poly(Propylene Carbonate) Polymer For High-Energy Lithium-Sulfur Battery

In view of low cost,environmental benignancy and ultrahigh theoretical specific capacity,lithium-sulfur batteries?LSBs?are expected to be one of the next-generation energy storage systems.However,the shuttle effect induced by lithium polysulfides?LiPSs?causes the irreversible loss of active materials,rapid fading of capacity,low coulombic efficiency and severe self-discharge,which is considered as one of the biggest obstacles for the application of LSBs.Employing the polymer electrolyte is one of the effective ways to solve this problem.Poly?propylene carbonate??PPC?as an environmentally friendly macromolecule material has attracted increasing attention in the field of lithium-ion batteries,while has not yet been reported in LSBs until now.On the other hand,S/PAN as a typical representative in sulfur-based composite cathode materials is deemed as one of the most promising cathode materials,owing to the simple preparation,high utilization of sulfur and coulombic efficiency.In this study,the S/PAN-Y10+5 composite is acquired by the improvement of preparation process.Meanwhile,nano-SiO₂ embedded PPC-based composite polymer electrolyte solution is prepared via liquid solution stirring,then G-PPC-CPE,M-Celgard-p and PPC-CPE are obtained by solution-casting methode,which finally have been applied in?S/PAN?/Li.The experimental results showed that S/PAN-Y10+5,which went through the tabletting and heating at 155°C for 10 h,exhibites an improved electrochemical performance.Compared to the LSBs with liquid electrolyte,the electrochemical performance of?S/PAN?/G-PPC-CPE/Li has been gotten a significant improvement.Particularly,?S/PAN?/G-PPC-CPE/Li delivers a reversible capacity of 597.3 mAh·g^-1_composite(1422.1 mAh·g^-1_sulfur)after 500 cycles at the current of 0.1 A·g^-11 and the capacity retention is 85%.Furthermore,compared to PEO-based composite polymer electrolyte PEO-CPE with nano-SiO₂,PPC-CPE shows a higher ionic conductivity(7.36×10^-4 S·cm^-1 at 50°C)and lithium ions transference number?0.83?;?S/PAN?/PPC-CPE/Li even discharges a reversible capacity of 554.2?1319.5?mAh·g^-1_composite(mAh·g^-1_sulfur)after 100 cycles at the current of 2.0 A·g^-1 with the capacity retention of 88.3%.In summary,PPC-based polymer electrolyte has an excellent compatibility with S/PAN composite and a high-energy lithium sulfur battery is expected to reach in the future.