Enhanced battery performance in manganese hexacyanoferrate by partial substitution

Manganese hexacyanoferrate (Mn-HCF) is a promising cathode material for sodium-ion secondary batteries (SIBs). We investigated the effects of partial substitution of Fe, Co, and Ni for Mn in Mn-HCF on the SIB rate and cycle performance. The discharge capacity is discernible at 50C in the substituted samples, while it disappears at 20C in the non-substituted samples. We ascribed the enhancement of the rate performance to the suppression of the Jahn-Teller distortion of Mn3+ and the resultant activation of the Mn reduction reaction. (C) 2016 Elsevier Ltd. All rights reserved.