Highly Conductive Freestanding Graphene Films as Anode Current Collectors for Flexible Lithium-Ion Batteries

The electrodes in lithium-ion batteries (LIBs) are typically films that are arranged on metal foil current collectors with a thickness of several tens of μm. Here, we report on the preparation of a thick free-standing graphene film synthesized by CVD as an alternative to Cu foil as an anode current collector. As a model system, MoS₂ anodes with a flower-like morphology were anchored onto the surface of the thick graphene film. A hybrid and binder free anode without a conventional metal current collector exhibited an excellent capacity value of around 580 mAh/g (@50 mA/g) and reasonable charge/discharge cyclability. The work presented here may stimulate the use of graphene films as replacements for conventional current collectors and additive free electrode in LIBs

Conformal Coating Strategy Comprising N‑doped Carbon and Conventional Graphene for Achieving Ultrahigh Power and Cyclability of LiFePO₄

Surface carbon coating to improve the inherent poor electrical conductivity of lithium iron phosphate (LiFePO₄, LFP) has been considered as most efficient strategy. Here, we also report one of the conventional methods for LFP but exhibiting a specific capacity beyond the theoretical value, ultrahigh rate performance, and excellent long-term cyclability: the specific capacity is 171.9 mAh/g (70 μm-thick electrode with ∼10 mg/cm² loading mass) at 0.1 C (17 mA/g) and retains 143.7 mAh/g at 10 C (1.7 A/g) and 95.8% of initial capacity at 10 C after 1000 cycles. It was found that the interior conformal N–C coating enhances the intrinsic conductivity of LFP nanorods (LFP NR) and the exterior reduced graphene oxide coating acts as an electrically conducting secondary network to electrically connect the entire electrode. The great electron transport mutually promoted with shorten Li diffusion length on (010) facet exposed LFP NR represents the highest specific capacity value recorded to date at 10 C and ultralong-term cyclability. This conformal carbon coating approach can be a promising strategy for the commercialization of LFP cathode in lithium ion batteries

Graphene/Acid Coassisted Synthesis of Ultrathin MoS₂ Nanosheets with Outstanding Rate Capability for a Lithium Battery Anode

Morphology-controlled MoS₂ nanosheets were successfully synthesized with the aid of graphene/acid coexistence by a one-pot hydrothermal method. The ultrathin MoS₂ nanosheets were self-assembled into a cockscomb-like structure with an exposed (100) facet on graphene sheets, which is in strong contrast to large aggregate MoS₂ plates grown freely on graphene sheets without acetic acid. The ultrathin MoS₂ nanosheets displayed excellent rate performance for Li storage (709 mAh·g^–1 capacity at 8320 mA·g^–1 discharging rate) and superior charge/discharge cyclability