Study On The Anode Materials Of Non-aqueous Lithium-carbon Dioxide Batteries

With the development of the world economy,environmental problems and energy crisis have further intensified,causing people to worry.In order to achieve sustainable development,scientists are committed to finding new,environmentally friendly and efficient energy sources,and lithium-carbon dioxide batteries are one of them.Lithium-carbon dioxide batteries discharge by reducing carbon dioxide,which has the dual effect of alleviating the greenhouse effect and the energy crisis.Due to its comparable energy density to gasoline,it is considered to have great potential as a substitute for gasoline.However,in practice,it faces the shortcomings of severe polarization and insufficient cycle stability.These problems limit its large-scale use.The use of highly efficient catalysts is one of the most commonly used methods to solve these problems.This paper mainly improves the performance of lithium-carbon dioxide batteries by doping boron atoms in carbon microspheres and supporting ruthenium particles.First,a series of boron-doped carbon microspheres were prepared by the reflux-calcination method.By changing the concentration of boric acid and calcination time,the optimal reaction conditions were explored.The results show that the boron-doped carbon microspheres obtained with the mass ratio of carbon spheres to boric acid of 1:5and calcined at 950℃for 4 h have the best catalytic performance.Because under this condition,it not only reduces the interference of boric acid on the growth of carbon microspheres,but also increases the defects of carbon microspheres and the content of boron.This is conducive to increasing the penetration and mass transfer process and active sites,while giving more storage space for the discharge product,so the battery performance is significantly improved.It can steadily run for 90 cycles at the current density of 200 m A g^-1,with a significantly reduced polarization.When the current density increases to 500 m A g^-1 and 800 m A g^-1,it can still achieve a cycle life of nearly50 weeks,but the polarization has increased.At the same time,Y1’can achieve an ultra-high discharge capacity of 17429 m A h g^-1 at a current density of 200 m A g^-1,which is almost 2.4 times that of bare carbon microspheres.When the current density increases to 500 m A g^-1 and 800 m A g^-1,the discharge capacity can also reach 11975 m A h g^-1and 4904 m A h g^-1,respectively,showing good rate performance.In addition,ruthenium particle loaded carbon microspheres with different contents（RC1,RC2,and RC3）were prepared by ethylene glycol reduction method.SEM shows that the content of ruthenium will affect its morphology on the surface of the carbon microspheres.When the content is small,it is a flower-like sphere.After loading ruthenium,the catalytic performance of the carbon microspheres is greatly improved.RC1 reaches an ultra-high discharge capacity of 26918 m A h g^-1 at a current density of200 m A g^-1.The electrochemical test results show that ruthenium has the dual catalytic function of simultaneously catalyzing the discharge reaction and the charge reaction,which not only reduces the charging voltage of the lithium-carbon dioxide battery to4.0 V,but also increases the discharge platform to 3.3 V,greatly reducing the polarization.