Enabling fast charging and all-climate Mn-containing olivine cathode via constructing hierarchically porous bulk architecture

Abstract

Fast charging and all-climate electrochemical behaviors are two of the most important issues of olivine cathodes for lithium ion batteries (LIBs) owing to inferior Li⁺ and electron conduction at a high current density or low temperature. Taking Mn-containing olivine cathode (LiFe_0.8Mn_0.2PO₄, LFMP) as an example, herein, we report a facile interconnected, hierarchically porous and highly conductive framework design strategy to construct an advanced bulk LFMP@graphene hybrid, realizing superior fast charging capability and wide temperature performance (−20∼80 °C). Such hybrids not only offer well-interconnected and highly conductive graphene networks, but also possess hierarchical porous interiors where the former ensures high-efficiency charge transfer between active components while the latter facilitates Li⁺ diffusion. Benefiting from these advantages, the obtained hybrids deliver superior rate capability (85.0 mAh g⁻¹ up to 20C) and high capacity retentions of 94.1 % after 3000 cycles at 10C (50 °C), and 91.7 % after 500 cycles at 5C (80 °C), and 93.6 % after 1300 cycles at 1C (−20 °C). This work provides an efficient strategy to design practical olivine cathode at the material level for fast charging and all-climate LIBs.