Enhancement of Y(5-x)Pr(x)Sb(3-y)M(y) (M = Sn, Pb) Electrodes for Lithium- and Sodium-Ion Batteries by Structure Disordering and CNTs Additives.

The maximally disordered (MD) phases with the general formula Y(5-x)Pr(x)Sb(3-y)M(y) (M = Sn, Pb) are formed with partial substitution of Y by Pr and Sb by Sn or Pb in the binary Y(5)Sb(3) compound. During the electrochemical lithiation and sodiation, the formation of Y(5-x)Pr(x)Sb(3-y)M(y)Li(z) and Y(5-x)Pr(x)Sb(3-y)M(y)Na(z) maximally disordered-high entropy intermetallic phases (MD-HEIP), as the result of insertion of Li/Na into octahedral voids, were observed. Carbon nanotubes (CNT) are an effective additive to improve the cycle stability of the Y(5-x)Pr(x)Sb(3-y)M(y) (M = Sn, Pb) anodes for lithium-ion (LIBs) and sodium-ion batteries (SIBs). Modification of Y(5-x)Pr(x)Sb(3-y)Sn(y) alloys by carbon nanotubes allowed us to significantly increase the discharge capacity of both types of batteries, which reaches 280 mAh · g(-1) (for LIBs) and 160 mAh · g(-1) (for SIBs), respectively. For Y(5-x)PrxSb(3-y)Pb(y) alloys in which antimony is replaced by lead, these capacities are slightly smaller and are 270 mAh · g(-1) (for LIBs) and 155 mAh · g(-1) (for SIBs), respectively. Results show that structure disordering and CNT additives could increase the electrode capacities up to 30% for LIBs and up to 25% for SIBs.