Polysaccharide Modified Cathodes for High-Capacity Rechargeable Nonaqueous Li–O2 Batteries

Nonaqueous rechargeable Li–O2 batteries are recognized as possible alternatives to the currently established Li-ion battery technology for next-generation traction by virtue of their high specific energy. However, the technology is still far from commercial realization mainly due to the performance-limiting reactions at the cathode. The insulating discharge product, Li2O2, can passivate the cathode leading to issues such as low specific capacity and early cell death. Herein, the −OH functionalities at the cathode, incorporated by polysaccharide addition, are shown to enhance the discharge capacity and cyclability. The −OH functional group (high pK a) at the cathode helps to stabilize the intermediate, LiO2, via an energetically favorable pathway and delays the precipitation to Li2O2, without any parasitic reaction, unlike the other reported low pK a additives. The role of the functionalities is studied using various experimental techniques and first principles density functional theory based studies. This approach provides a rational design route for the cathodes that provide high capacities for the emergent Li–O2 batteries.