Micro Silicon–Graphene–Carbon Nanotube Anode for Full Cell Lithium-ion Battery

Abstract

An electrochemically stable hybrid structure material consisting of porous silicon (Si) nanoparticles, carbon nanotubes (CNTs), and reduced graphene oxide (rGO) is developed as an anode material (Si/rGO/CNT) for full cell lithium-ion batteries (LIBs). In the developed hybrid material, the rGO provides a robust matrix with sufficient void space to accommodate the volume change of Si during lithiation/delithiation and a good electric contact. CNTs act as a mechanically stable and electrically conductive support to enhance the overall mechanical strength and conductivity. The developed Si/rGO/CNT composite anode has been first tested in half cell and then in full cell lithium-ion batteries. In half cell, the composite anode shows a high reversible capacity of 1100 mAh g−1 with good capacity retention over 500 cycles when cycled at 1 A g−1. In a full cell lithium-ion battery paired up with LiNi1/3Mn1/3Co1/3O2 (NMC) cathodes, the composite anode shows a specific charge capacity of 161.4 mAh g−1 and a discharge capacity of 152.8 mAh g−1, respectively, with a Coulombic efficiency of 94.7%.

Stable and High-Capacity Si Electrodes with Free-Standing Architecture for Lithium-Ion Batteries

“…The gravimetric discharge capacity exhibited 1942, 2093, 2180, and 2199 mAh g –1 Si corresponding to 1st, 5th, 10th, and 30th cycles, respectively. Up to 30 cycles, a similar behavior to the previous studies using a graphene oxide was obtained in which Si reacted with Li in the activation process. , To further understand the cycling stability of free-standing anodes, we compared the cyclability of the five anode active materials, which are c-Si NPs, c-bulk Si, Si NPs, bulk Si, and mesocarbon microbeads (MCMB) graphite (Figure d). Graphite electrode showed a capacity of 150 mAh g –1 at 1 C with Coulombic efficiency of 99.9%.…”

Carbon-free high-loading silicon anodes enabled by sulfide solid electrolytes

“…To demonstrate the importance of eliminating carbon in the anode, as well as the passivating nature of the Si-SSE interface, we characterized and quantified the SEI products from SSE decomposition with and without the presence of carbon additives. As most literature reports adopt Si composites containing between 20 and 40 wt % carbon additives (5,(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), this was used as a basis for comparison against carbonfree mSi. Although Li metal is typically used as the counterelectrode in liquid electrolyte studies, its low critical current density in ASSBs make it unsuitable for studying our system (32,33).…”

“…(5,7) While improvements have been reported in numerous half-cell studies, the uncontrolled amounts of lithium excess used were difficult to determine, which makes it challenging to evaluate the strategies proposed. Amongst reports that demonstrated stable cycling in full cells (5,(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), most adopt composites containing between 60 to 80 wt% Si, with carbon additives and polymeric binders typically making up the rest of the electrode. Additionally, most reported full cell performances are limited to 100 cycles, apart from a few that demonstrated longer cycle life using various pre-lithiation strategies to compensate for Li + inventory losses.…”

“…Additionally, most reported full cell performances are limited to 100 cycles, apart from a few that demonstrated longer cycle life using various pre-lithiation strategies to compensate for Li + inventory losses. (9,14,18) While pre-lithiation is believed to be effective to extend cycle life, the ideal Si anode should be composed of pristine µSi particles that do not require further treatment, reaping the benefits of low costs, ambient air-stability and environmentally benign properties. To realize this potential, it is vital to address the two key challenges of µSi anodes: a) achieving high µSi loading with minimal incorporation of carbon and binder, b) stabilizing interfacial growth originating from volume expansion and Li + consumption.…”

“…Improvements have been reported in numerous half-cell studies, but the varied amounts of lithium excess make it challenging to evaluate the effectiveness of each strategy. Among reports that demonstrated stable cycling in full cells (5,(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), most are limited to 100 cy-cles, apart from a few that demonstrated longer cycle life using various prelithiation strategies to compensate for Li + inventory losses (9,14,18). Although prelithiation can be effective to extend cycle life, the ideal Si anode should be composed of pristine microsilicon (mSi) particles that do not require further treatment, reaping the benefits of low costs, ambient air stability, and environmentally benign properties.…”