Mesoporous SiO2 Anode Armour for Lithium Oxygen Battery

We are reporting a new lithium (Li) anode protective strategy using mesoporous silicon dioxide (mSiO2) to extend the operation lifetime for Li oxygen batteries (LOBs). The fabrication method is simple and easy for mass production. The mSiO2 protective layer inhibits the growth of Li dendrites and prevents the intrinsic Li corrosion phenomenon that occurs in all Li-metal-based batteries during charge/discharge cycles, the porous structure of nanoparticles within the mSiO2 also actively created parallel pathways for Li+ transport thus enhancing the mass transfer. Propylene carbonate/Li with a 100 μL drop amount of mSiO2 protective layer (mPL100) showed excellent per26 formance in the Li||Li battery charge/discharge cycle test, withstanding 2,276 hours of continuous operation, almost 16 times longer than the battery without the protective layer, and the LOB charge/discharge cycle test with the mSiO2 protective layer reached 382 cycles, another significant increase of 6.2 times over the unprotected battery, the full discharge capacity also reached 56,902 mAh g-1 30 that is nearly 19 times higher than the unprotected cell. Because the mSiO2 made Li+ flux more homogeneous meanwhile promoting the uniform distribution of positive electrode products and accelerating their decomposition, thus the overpotential is reduced. This layer also blocked any H2O and peroxide molecules which attack the Li anode, therefore the retention of Li anode has been kept at a satisfactory level.