Sol-gel derived nano-crystalline CaSnO₃ as high capacity anode material for Li-ion batteries

Abstract

CaSnO₃ with the distorted-perovskite structure was prepared by sol-gel and high temperature solid-state reaction and electrochemical properties were studied in cell with Li as counter electrode. The sol-gel method gave uniform nano-crystallites (200-300 nm) of CaSnO₃ and was shown to deliver a reversible capacity of 380 mAh/g (0.005-1.0 V; 60 mA/g) with good cycling stability up to 45 cycles. The observed capacity involved in the first-discharge and the reversible capacity values during subsequent charge-discharge cycles show that the electrochemical process in CaSnO₃ is similar to other Sn-containing mixed oxide systems, viz., an initial structural reduction with Sn-metal formation followed by reversible Li-Sn alloy formation. The performance with respect to the attainable capacity, its retention on charge-discharge cycling and rate capability is better than the previously reported best-performing bulk Sn-oxide or ATCO starting materials which reveals that the perovskite structure and Ca-ion play a beneficial role.