Germanium on seamless graphene carbon nanotube hybrids for lithium ion anodes

A New Anode for Lithium‐Ion Batteries Based on Single‐Walled Carbon Nanotubes and Graphene: Improved Performance through a Binary Network Design

“…The semicircle was associated with the cell'sh igh-frequency charge-transfer properties, whilst the low-frequency skew line corresponded to ion transport of the active ions. [8][9][10][11][12][13][14][15][16][17][18][19][20] Furthermore, the SWCNT-GF electrode was used for 2200 cycles at ar elatively high current density of 5Ag À1 ,a nd stable cycling performance was observed, with as pecific capacity of 189 mA hg À1 after 2200 cycles (Figure 5b). Allt hree electrodes exhibited very low chargetransfer resistance (SWCNT foam:2 7.9 W;S WCNT-GF:5 3.6 W; GF:87.2 W), which was attributed to the high electrical conductivity and 3D porous structureo ft hese electrodes.…”

“…As shown in Figure 4d,a ll of the plotsw erec omprised of a semicircle and as kew line. [10][11][12][13][14][15][16] The cycling performances of SWCNT-GF,p ure SWCNT foam, and GF electrodes are shown in Figure 5a.F or the SWCNT-GF electrode, the specific capacity quicklyd ecreased within the first 50 cycles and then maintainedastable, reversible specific capacityo vert he following cycles. [25][26][27][28] The EIS diagram were fitted by using the circuitry model (Figure 4d,i nset), in which R s denotes the current collector and electrolyte resistance, R f and Q 1 denote the SEIlayer resistancea nd the constant-phase element, respectively, R ct and Q 2 denotet he charge-transfer resistance and doublelayer capacitance, respectively,a nd Z W denotes the Warburg impedance.…”

“…The chargetransfer resistance of SWCNT-GF was much lower than that of other carbon-basede lectrodes. [10][11][12][13][14][15][16] The cycling performances of SWCNT-GF,p ure SWCNT foam, and GF electrodes are shown in Figure 5a.F or the SWCNT-GF electrode, the specific capacity quicklyd ecreased within the first 50 cycles and then maintainedastable, reversible specific capacityo vert he following cycles. Thisi nitial capacity loss during the first 50 cycles was attributedt ot he continuous trapping of lithium ions and the reformation of at hick SEI layer.F or the SWCNT-GF electrode, ah igh reversible capacity of 606 mA hg À1 remained after 1000 cycles, with ac apacity retention of 90 %, even at ahigh current density of 1Ag À1 .Inaddition, the SWCNT and GF electrodes both exhibited excellent cycling stability,w ith capacity retention of 89 %a nd 77 %o ver 1000 cycles, respectively.F irst, al ow rate (0.1 Ag À1 )w as used to fully activate the electrode and then ah igh rate was used for the cyclability tests.…”

“…[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] For example, single-walled carbon nanotube "paper" that is prepared by using vacuum filtration has been used as anodes in LIBs, thereby showingareversible dischargec apacity of about 400 mA hg À1 at ac urrent density of 0.08 mA cm À2 . [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] For example, single-walled carbon nanotube "paper" that is prepared by using vacuum filtration has been used as anodes in LIBs, thereby showingareversible dischargec apacity of about 400 mA hg À1 at ac urrent density of 0.08 mA cm À2 .…”

“…Carbon nanomaterials, especially graphene and carbon nanotubes, are considered to be favorable alternatives to graphite anodes in lithium-ion batteries, owing to their high specific surfacea rea, electrical conductivity,a nd excellent mechanicalf lexibility. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] For example, single-walled carbon nanotube "paper" that is prepared by using vacuum filtration has been used as anodes in LIBs, thereby showingareversible dischargec apacity of about 400 mA hg À1 at ac urrent density of 0.08 mA cm À2 . [23] Despite its low capacity,t his flexible paper can be used directly as binder-free electrodes and holds great potentialf or applicationsi nf lexible batteries.…”