Development of Quasi-solid-state Na-ion Battery Based on DPEPA-derived Gel Polymer Electrolyte
Compared to Li-ion batteries,Na-ion batteries hold significant advantages and market value for achieving low-cost and large-scale energy storage,thanks to the utilization of cheap and abundant Na resources.However,the use of highly flammable liquid electrolytes with leaky risk raises safety concerns for conventional Na-ion batteries under abuse conditions such as mechanical damage,short-circuiting,and thermal runaway.Limited electrochemical stability of liquid electrolytes also hinders further enhancement of the performance of Na-ion batteries for practical use.This study reports a facile way for the preparation of high-performance gel polymer electrolyte(GPE)by thermal-driven radical in-situ polymerization of dipentaerythritol penta-/hexa-acrylat(DPEPA).This GPE exhibits an ionic conductivity of 1.97 mS·cm-1,a Na+transference number of 0.66,and a broad electrochemical stability window.The DPEPA displays a lower lowest unoccupied molecular orbit(LUMO)energy level than that of ethylene carbonate(EC)and diethyl carbonate(DEC)solvents,allowing for its preferential decomposition alongside NaPF6 on the anode surface.This leads to a stable organic-inorganic composite film of solid-state electrolyte interphase,inhibiting the decomposition of electrolyte solvents on the anode surface.The quasi-solid-state Na-ion battery employing Na(Ni 1/3Fe1/3Mn 1/3)O2(NFM)cathode and hard carbon(HC)anode in this GPE exhibits a high capacity retention rate of 92％after 300 stable cycles at a current density of 120 mA·g-1,while achieving the specific capacities of 99-120 mAh·g-1 within a wide temperature range of 20-80 ℃.In-situ X-ray diffractometer analysis reveals the highly reversible structural evolution of the NFM cathode during Na storage and the"adsorption-pore-filling"mechanism of Na+storage in the HC anode.All data in this research demonstrates that introducing polymers with low LUMO energy levels proves an effective approach to enhance the electrochemical stability of solid-state Na-ion batteries while improving cell safety.
万方数据
维普
