The effects of oxygen pressure on the discharge performance of potassium–oxygen batteries

Abstract

Applying high oxygen pressure drastically improves the discharge performance of potassium-oxygen batteries. High oxygen pressure can also prevent parasitic reactions leading towards K2SO4 and K2CO3 induced by oxygen depletion within the cathode.

A Model of the Potassium-Oxygen Battery and its Application in Cathode Design

“…This indicates strong oxygen transport limitations at the higher rates. 25 In Figs. 3d-3f, the simulated KO 2 volume fraction θ KO ,dep 2 after discharge is displayed.…”

“…From previous reports, it is apparent that oxygen transport is governing the discharge performance. 25 A simulation of the oxygen concentration c O2 along discharge was conducted. The c O2 distributions at different depths of discharge (DoD) for both J = 0.1 mA cm −2 and J = 0.5 mA cm −2 are displayed in Fig.…”

“…6 In DMSO-based electrolytes, KO 2 may form dendritic structures on the cathode carbon fibers up to tens of μm in length. 20,25,26 In consequence, the growth mechanism proposed by Wang et al assumes sufficient conductivity of the discharge product to enable ORR at the tip of the dendrite, which differs from the predictions of theoretical studies. 6 Our previous works observed that high degrees of pore volume filling can be achieved in a cathode material with a mean pore size of 20 μm when sufficient oxygen mass transport throughout the porous cathode is enabled.…”

“…6 Our previous works observed that high degrees of pore volume filling can be achieved in a cathode material with a mean pore size of 20 μm when sufficient oxygen mass transport throughout the porous cathode is enabled. 25,26 The maximum achievable discharge capacity of KOB is inherently limited by the total pore volume of the cathode material due to the deposition of solid KO 2 . In addition, the low electronic conductivity of KO 2 will cause the passivation of the cathode surface area and limited rate capability.…”

Evolving aprotic Li–air batteries

“…Oxygen pressure could play a very significant role in performance. 113,114 Higher pressure enables more O 2 to reach the active carbon sites and thus a higher discharge capacity. Hickey et al found that the discharge capacity increased by 10% as the O 2 pressure increased from 1 atm to 10 atm.…”