Study On Assembly And Performance Of Quasi-solid Zinc-manganese Battery

Zinc ion batteries are considered as a promising power source due to its friendliness,low-cost and safety.However,the practical application of a zinc ion battery is impeded by the Zn dendrite growth and side reactions at the electrode/electrolyte interface.In addition,when zinc-ion batteries are used as energy storage devices in flexible wearable electronic products,they are vulnerable to physical damage such as pinpricking,bending,stretching and shearing,which may lead to battery failure or even cause serious safety problems.To solve these problems,we design a zinc ion battery with excellent energy-storage performance and outstanding reliability by using a novel self-healable hydrogel electrolyte,which provided a novel strategy for prolonging the life of energy storage devices.In this paper,an aqueous manganese-based zinc ion battery was assembled by using alpha-manganese dioxide??-MnO₂?as the cathode and zinc foil as the anode firstly.?-MnO₂ with different morphologies was prepared by solid-phase synthesis,solution coprecipitation and hydrothermal methods.Among them,nanowire?-MnO₂prepared by hydrothermal method performed best.Its maximum specific capacity can reach 265 mAh g^-1.After 200 cycles of galvanostatic charge/discharge at 0.5 C,the specific capacity is 233 mAh g^-1,and the capacity retention rate is 91.8%.Under the condition of high discharging current at 5 C,the specific capacity can reach 107 mAh g^-1.In addition,the best electrolyte of the battery was found by changing the composition and concentration of the electrolyte.When the electrolyte was composed of1.0 mol L^-1 zinc nitrate and 0.2 mol L^-1 manganese sulfate,the battery performed the flattest discharging platform,the highest specific capacity and the best cycling stability.Based on the research of aqueous zinc-manganese batteries,a quasi-solid zinc-manganese battery with self-healable hydrogel electrolyte based on dynamic coordination bond of iron ions was further constructed.The maximum mechanical tensile strength of the hydrogel electrolyte is 115 kPa,which can be stretched 5-7 times.And its mechanical properties could have been basically restored to the initial state within 10 min after fracture-contact.After self-healing,the microcosmic morphology,mechanical properties and electrical conductivity of the electrolyte can all recover to the initial state.Moreover,the quasi-solid zinc ion battery can withstand at least 5 times of cut-repair without affected its electrochemical performance.The specific capacity of the hydrogel zinc-manganese battery can reach 212 mAh g^-1,even though it is slightly lower than the aqueous battery,the hydrogel battery showed better cycling stability.After cycling for 1000 cycles at 1.0 C,the battery still delivered a specific capacity of177 mAh g^-1,showing a retention rate of 83.3%.While the specific capacity retention rate of the aqueous battery has dropped to 49%after 500 cycles.And it exhibited a specific capacity of 151 mAh g^-1 at the rate of 5 C.It is 40%higher compared with a control zinc ion battery using aqueous Zn?NO₃?₂/MnSO₄ electrolyte.