Porous Graphene Sponge Additives for Lithium Ion Batteries with Excellent Rate Capability

Abstract

Rate capability as well as power performance of lithium ion batteries (LiBs) is becoming more and more important, especially as the application targets of LiBs move from mobile devices to transportation, such as EVs and HEVs. In this research, we report porous graphene sponge additives for both anode and cathode materials for better rate performance. The charge capacity retention improved from 56% to 77% at 6C and from 7% to 45% at 10C with 0.5 wt% added to the anode, while the discharge capacity retention at the 6C rate improved from 43% to 76% and the 10C rate discharge improved from 16% to 40% with the same amount of MG added to the cathode. The cyclability at high rate was also improved with the MG additive. Moreover, preparation of the MG was facile, cost-effective, and compatible with commercially available active materials. These results demonstrate the suitability of MG for use with LiB additives to ensure better rate capability and high rate cyclability.

Graphene-Like-Graphite as Fast-Chargeable and High-Capacity Anode Materials for Lithium Ion Batteries

“…Therefore, we concluded that Li ions are stored on both sides of graphene layers in them. More recently, similar materials have been used for the electrode of electric double-layer capacitors exhibiting higher capacity and rate capability 31 , 32 . Larger ions, such as tetrafluoroborate (BF 4 − ) and tetramethylammonium ((CH 3 ) 4 N + ), are also intercalated, which is considered resulting from the reduced van der Waals energy between adjacent graphene layers.…”

Graphene Foam Current Collector for High-Areal-Capacity Lithium–Sulfur Batteries

“…Although such a lower thickness in Al/C1 foil naturally facilitates better access to Li ions, increasing the S loading beyond 0.3 mg cm –2 without delamination is highly difficult. A typical Nyquist plot is shown in Figure c in which the first semicircle is due to the SEI layer and the second semicircle is due to charge transfer at the electrolyte and electrode interface. − Modeling the Nyquist plot with the Randles circuit shown in Figure S6, the resistances for each electrode were deduced and are listed in Table S3. The series ( R s ) and SEI ( R SEI ) resistances of the GF0 cathode were found to be higher than that of Al/C1 and attributed to unfilled pores in GF0 because of the low SPAN loading of 0.1 mg cm –2 .…”

Graphene: A promising candidate for charge regulation in high-performance lithium-ion batteries

“…Due to the macroscopic morphology obtained by assembly, many properties can be obtained and utilized to enhance the efficiency of charge transport in LIBs, which can be summarized as the following advantages: 1) The large specific surface area of graphene-based macrostructures provide abundant electrochemical reaction interfaces for Li + storage; 2) The interconnected graphene lamellae within graphene-based macrostructures can construct efficient and continuous electronic conductive networks to collect/transport electrons from/to the active particles during the charge and discharge processes; 3) the rich pore structures formed from the interlinked graphene nanosheets allow for the penetration of electrolyte and provide short diffusion distances and multi-channels for ion transfer, effectively facilitating the diffusion of Li + . For instance, Qian Cheng et al reported a honeycomb-like porous graphene sponge additive prepared from chemically derived graphene sheets for both anode and cathode materials [91]. The charge capacity retention and cyclability at high rate improved greatly with the addition of porous graphene sponge additives, which was attributed to the excellent electric conductivity, high specific surface area, and high ability of electrolyte absorption of graphene sponge additives.…”