High-rate and ultralong-life Mg–Li hybrid batteries based on highly pseudocapacitive dual-phase TiO2 nanosheet cathodes

• Published in: Journal of power sources Vol. 506; p. 230118
• Main Authors: Vincent, Mewin, Avvaru, Venkata Sai, Rodríguez, Miguel Castillo, Haranczyk, Maciej, Etacheri, Vinodkumar
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.09.2021
• Subjects: Hybrid battery; Intercalation; Interfaces; Nanosheets; Pseudocapacitance; Hybrid battery; Interfaces; Nanosheets; Intercalation; Pseudocapacitance
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2021.230118

Although Mg–Li hybrid batteries are proposed as an alternative to Mg-batteries, the lack of dual-ion compatible cathodes are limiting their practical application. Herein, we report a high-rate and ultralong-life Mg–Li hybrid battery based on a dual-phase TiO2 cathode. Highly pseudocapacitive hierarchical two-dimensional TiO2 consists of anatase (60%) and bronze (40%) nanocrystallites forming interfaces due to crystal structure mismatch. This dual-phase hierarchical cathode exhibits excellent pseudocapacitance (up to 92%), specific capacities (235 mAh/g @ 25 mA/g), rate performance (120 mAh/g @ 1A/g) cycling stability (~87% after 3000 cycles @ 1A/g) and coulombic efficiency (~100%). These results are vastly superior to the previously reported values for TiO2 based Mg–Li hybrid battery cathodes. Only minimal structural changes are observed during the charge-discharge of two-dimensional TiO2 electrode. Outstanding electrochemical performance of dual-phase TiO2 nanosheet cathode is attributed to the superior pseudocapacitive Mg/Li-ion diffusion through nanointerfaces between anatase and bronze crystallites. While other structural features such as 2D-morphology, ultrathin nature, mesoporosity, and high surface area act as secondary factors. The demonstrated approach for efficient pseudocapacitive Mg/Li-ion intercalation enhanced by nanointerfaces can be further exploited in the development of other high performance electrodes for advanced Mg–Li hybrid batteries. [Display omitted] •High-rate and ultralong-life Mg–Li hybrid battery is presented.•Dual-phase TiO2 nanosheet cathode exhibited outstanding Mg/Li-ion storage.•Anatase-bronze nanointerfaces caused excellent pseudocapacitance.•This tactic provides new opportunities to design advanced Mg–Li hybrid batteries.