Progress towards high-power Li/CF_xbatteries: electrode architectures using carbon nanotubes with CF_x

Abstract

Carbon monofluoride (CFx) has a high energy density, exceeding 2000 W h kg(-1), yet its application in primary lithium batteries is limited by its power capability. Multi-walled carbon nanotubes (CNTs) are appealing additives for high-power batteries, due to their outstanding electronic transport properties, high aspect ratio necessitating low volume fraction for percolation, and high tensile strength. This perspective describes the current state of the art in lithium-carbon monofluoride (Li/CFx) batteries and highlights the opportunities for the development of high-power Li/CFx batteries via utilization of carbon nanotubes. In this report, we generated several electrode architectures using CFx/CNT combinations, and demonstrated the effectiveness of CNTs in enhancing the rate capability and energy density of Li/CFx batteries. First, we investigated the resistivity of CFx combined with CNTs and compared the CFx/CNT composites with conventional carbon additives. Second, we built CFx-CNT electrodes without metallic current collectors using CNTs as substrates, and compared their electrochemical performance with conventional CFx electrodes using aluminum foil as a current collector. Furthermore, we fabricated multi-layered CNT-CFx-CNT composite electrodes (sandwich electrodes) and studied the impact of the structure on the performance of the electrode. Our work demonstrates some of the opportunities for utilization of CNTs in CFx electrodes and the resultant implementation of CFx as a battery cathode in next-generation high-power batteries.

Reaction mechanism and structural evolution of fluorographite cathodes in Li/Na/K batteries

“…According to previous work, LiF crystals have been formed and detected using XRD analysis and NMR spectra in liquid Li ion primary batteries during discharge process. 8,9,13,16,17 Considering the all-solid-state environment in in situ TEM, amorphous LiF is formed in the solid-state Li-CF x system, which is consistent with that reported by Rangasamy. 32 As for the formed Li 2 O, Li will diffuse along the surface of the materials during in situ TEM, and the active Li will react with trace O 2 in the TEM instrument, resulting in Li 2 O formation in CF x .…”

“…The peak at 13° is assigned to the (002) re ection of the CF x . 9,10,24 The peak at 41° corresponds to (100) and (011) re ections, which is related to the C-C bond length and CF interlayer distance. Figure 1c shows a typical TEM bright eld image of the CF x material with large sheet-like topography, and the corresponding high resolution TEM image ( Figure 1d) shows a disordered amorphous structure.…”

Potassium‐Based α‐Manganese Dioxide Nanofiber Binder‐Free Self‐Supporting Electrodes: A Design Strategy for High Energy Density Batteries

“…[5,6] One strategy to eliminatet he binder and current collector is to anchor or grow the redox-activem aterial on ac onductive fibrousn etwork or support,f or which the redox-active materials are either synthesized in situ, directly deposited by electrodeposition, or attached ontot he conductive supports. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] Ty pical conductive supports include nanofibers (i.e., carbon nanotubes),n anosheets (i.e., reduced graphene oxide),a nd fibrous carbon sources with network-like structures.D ifferentf rom previous binder-free and free-standing electrodes tudies,o ur approach uses redox-activeh igh aspect ratio potassium-containing a-MnO 2 -typem anganese dioxide nanofibers (K-OMS-2)a st he structural element, and this results in binder-free self-supporting( BFSS) cathodes.T he electrochemical behavior was tested by galvanostatic dis-charge/charge testing, electrochemical impedance spectroscopy (EIS),and galvanostatic intermittenttitration-type testing. By eliminatingt he binders and current collector, cells with K-OMS-2 BFFS cathodes displayed enhanced specifice nergies (3-folda tl ower rates,1 0-fold at higher rates) relative to cells with conventionally constructed cathodes (Figure 1, inset).…”

Fluorinated graphene/sulfur hybrid cathode for high energy and high power density lithium primary batteries

“…[1][2][3] The carbon uoride (CF x ; 0 < x < 1.3) cathode has many unique advantages, such as a high theoretical potential, a wide operational temperature range, and a at discharge potential. 4,5 The CF x (x ¼ 1) cathode has an open circuit potential of 3.0-3.5 V vs. Li + /Li in most non-aqueous liquid electrolytes.…”