CdPS 3 nanosheets-based membrane with high proton conductivity enabled by Cd vacancies

Vacancies enhance proton conductivity Proton-exchange membranes (PEMs) allow for the transport of protons while acting as electrical insulators and ensuring that reactants are kept apart; therefore, they are a key component in devices such as low-temperature fuel cells. PEMs are typically made from polymers or materials embedded in a polymer matrix and need to operate in conditions of very high humidity. Starting with an inorganic, layered material, CdPS 3 , Qian et al. show that the removal of a small amount of cadmium introduces vacancies that greatly increase the proton conductivity of the PEMs (see the Perspective by Wang and He). The process works for manganese-based membranes as well, and high lithium ion transport was also observed. Science , this issue p. 596 ; see also p. 525