A Carbon‐ and Binder‐Free Nanostructured Cathode for High‐Performance Nonaqueous Li‐O₂ Battery

Abstract

Operation of the nonaqueous Li–O2 battery critically relies on the reversible oxygen reduction/evolution reactions in the porous cathode. Carbon and polymeric binder, widely used for the construction of Li–O2 cathode, have recently been shown to decompose in the O2 environment and thus cannot sustain the desired battery reactions. Identifying stable cathode materials is thus a major current challenge that has motivated extensive search for noncarbonaceous alternatives. Here, RuOx/titanium nitride nanotube arrays (RuOx/TiN NTA) containing neither carbon nor binder are used as the cathode for nonaqueous Li–O2 batteries. The free standing TiN NTA electrode is more stable than carbon electrode, and possesses enhanced electronic conductivity compared to TiN nanoparticle bound with polytetrafluoroethylene due to a direct contact between TiN and Ti mesh substrate. RuOx is electrodeposited into TiN NTA to form a coaxial nanostructure, which can further promote the oxygen evolution reaction. This optimized monolithic electrode can avoid the side reaction arising from carbon material, which exhibits low overpotential and excellent cycle stability over 300 cycles. These results presented here demonstrate a highly effective carbon‐free cathode and further imply that the structure designing of cathode plays a critical role for improving the electrochemical performance of nonaqueous Li–O2 batteries.

Carambola-shaped VO2 nanostructures: a binder-free air electrode for an aqueous Na–air battery

“…It was found that cells with spherical VO 2 nanostructures show a higher overpotential gap of 0.98 V than those with the carambola-shaped VO 2 nanostructures (0.64 V) (Supplementary Figure S15). Additionally, the absence of the binder and presence of the rGO support also improves the charge transport by enhancing the electrode conductivity 50,51 and thereby leading to high round trip efficiency and low terminated discharge voltage.…”

Electrolytes for Rechargeable Lithium–Air Batteries

“…As presented in Figure 1, Li-air batteries are composed of cathodes,e lectrolytes,a nd Li anodes.T he cathode should be porous and contain enough space to accommodate the insoluble discharge product Li 2 O 2 . [4][5][6][7][8][9][10] O 2 ,a st he active material of the cathodes,i sp resumed to be obtained from the open air to facilitate ah igh capacity. [1] In non-aqueous systems,p ure O 2 is widely used in most laboratory-scale experiments to prevent other components in air,e specially H 2 Oa nd CO 2 ,f rom interfering with the desired electro-chemical behavior.…”

Influence of Binders and Solvents on Stability of Ru/RuOx Nanoparticles on ITO Nanocrystals as Li–O2 Battery Cathodes

“…[25] Av ariety of "carbon-free" cathodes have been proposed to address such issues. These have been based on nanoporous Au, [26] TiC, [27] ruthenium/indium tin oxide (Ru/ITO), [28] Ru/Sb-doped tin oxide, [29] nanoneedle arrays decorated with nanoflakes of transition-metal oxides, [30] RuO 2 /mesoporous TiO 2 , [31] Ru/TiS 2 nanonets, [32] RuO x /titanium nitride nanotube arrays [33] and metallic mesoporousp yrochlore. [34] Of great significance is the sensitivity of the electrochemical response of the Li-O 2 cell to the electrolyte composition.…”