Electrochemical and 119Sn Mössbauer studies of the reaction of Co2SnO4 with lithium

The electrochemical reaction of Co2SnO4 with Li is studied by using ex-situ 119Sn Mössbauer spectroscopy. During the progress of the first discharge process between 3 and 0 V, the relative intensity of the signal originated from Sn(IV) atoms continuously decreases. A new signal which is attributed to cobalt–tin intermetallic compounds emerges, and the relative intensity of this signal increases between 3 and 0 V. At around 0 V, the signal corresponding to Sn(IV) atoms is not observed, while a lithium-rich tin phase appears. After charging up to 3 V, the tin atoms are re-oxidized and Sn(IV) ions are formed. Reversible capacities over 800 mAh g−1 are achieved in the first cycles. cobalt–tin compounds are promising negative electrodes for lithium-ion batteries.