Capacitive contribution to Li-storage in TiO2 (B) and TiO2 (anatase)

• Capacitive parts of cyclic voltammograms of Li-storage were deconvoluted.
• TiO2 (B) has by 30% larger capacitive contribution than anatase.
• The capacitive Li-storage in TiO2 (B) occurs in bulk crystal.

Analysis of cyclic voltammograms of Li insertion into TiO2 (B) and anatase provides information about capacitive contributions to overall charge of Li-storage. The enhancement of 30% is found in capacitive contributions (normalized to the total stored charges) in TiO2 (B) compared to that in anatase, in spite of ca. three times smaller surface area of the former. Different charging mechanism explains facilitated Li+ insertion in TiO2 (B). The difference is caused mainly by pseudocapacitive Li-storage in the bulk TiO2 (B). Deconvolution of cyclic voltammograms also indicates different capacitive contributions of the two voltammetric peaks, S1 and S2 of TiO2 (B). These results provide novel insight into the Li-storage in TiO2 (B) and its difference from that in anatase.

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