[Abstract]

Mixed transition metal oxides are promising anodes to meet high-performance energy storage materials; however, their widespread uses are restrained owing to limited theoretical capacity, restricted synthesis methods and templates, low conductivity, and extreme volume expansion. Here, Mn_3-xFe_xO₄ nanosheets with interconnected conductive networks are synthesized via a novel self-hybridization approach of a facile, galvanic replacement-derived, tetraethyl orthosilicate-assisted hydrothermal process. An exceptionally high reversible capacity of 1492.9 mAh g⁻¹ at 0.1 A g⁻¹ is achieved by producing Li-rich phase through combined synergistic effects of amorphous phases with interface modification design for fully utilizing highly spin-polarized surface capacitance. Furthermore, it is demonstrated that large surface area can effectively facilitate Li-ion kinetics, and the formation of interconnected conductive networks improves the electrical conductivity and structural stability by alleviating volume expansion. This leads to a high rate capability of 412.3 mAh g⁻¹ even at an extremely high current density of 10 A g⁻¹ and stable cyclic stability with a capacity up to 921.9 mAh g⁻¹ at 2 A g⁻¹ after 500 cycles. This study can help to overcome theoretically limited electrochemical properties of conventional metal oxide materials, providing a new insight into the rational design with surface alteration to boost Li-ion storage capacity.

DOI: 10.1002/adfm.202300143

Link: https://onlinelibrary.wiley.com/doi/10.1002/adfm.202300143