Challenges Lithium–air battery

1 challenges

1.1 cathode
1.2 anode
1.3 electrochemical
1.4 stability

challenges

as of 2013, many challenges confronted designers of li-air batteries.

cathode

most of current limits in li-air battery development @ cathode, source of potential advantages. incomplete discharge due blockage of porous carbon cathode discharge product such lithium peroxide (in aprotic designs) serious. several modes of precipitates elucidated , modeled. parameter, da, defined measure variations of temperature, species concentration, , potentials.

the effect of pore size , pore size distribution remains poorly understood.

catalysts have shown promise in creating preferential nucleation of li

2o

2 on li

2o, irreversible respect lithium.

atmospheric oxygen must present @ cathode, contaminants such water vapor can damage it.

anode

the main challenge in anode development preventing anode reacting electrolyte. alternatives include new electrolyte materials or redesigning interface between electrolyte , anode. other challenges pertain particular choice of anode material, such silicon or lithium. great concern silicon anodes large volume expansion (320%) experiences alloys lithium. lithium anodes, dendritic lithium deposits can form, decreasing energy capacity or triggering short circuit.

electrochemical

in current cell designs, charge overpotential higher discharge overpotential. significant charge overpotential indicates presence of secondary reactions. thus, electric efficiency around 65%.

catalysts such manganese dioxide (mno

2), co, pt, , au can potentially reduce overpotentials, effect poorly understood. several catalysts improve cathode performance, notably mno

2. mechanism of improvement unknown, may alter structure of oxide deposits.

significant drops in cell capacity increasing discharge rates issue. decrease in cell capacity attributed kinetic charge transfer limits. since anodic reaction occurs quickly, charge transfer limits thought occur @ cathode.

stability

long-term battery operation requires chemical stability of cell components. current cell designs show poor resistance oxidation reaction products , intermediates. many aqueous electrolytes volatile , can evaporate on time. stability hampered in general parasitic chemical reactions taking place instance involving reactive oxygen.