Silicon is considered a most promising anode material for overcoming the theoretical capacity limit of carbonaceous anodes. The use of nanomethods has led to significant progress being made with Si anodes to address the severe volume change during (de)lithiation. However, less progress has been made in the practical application of Si anodes in commercial lithium‐ion batteries (LIBs). The drastic increase in the energy demands of diverse industries has led to the co‐utilization of Si and graphite resurfacing as a commercially viable method for realizing high energy. Herein, we highlight the necessity for the co‐utilization of graphite and Si for commercialization and discuss the development of graphite/Si anodes. Representative Si anodes used in graphite‐blended electrodes are covered and a variety of strategies for building graphite/Si composites are organized according to their synthetic methods. The criteria for the co‐utilization of graphite and Si are systematically presented. Finally, we provide suggestions for the commercialization of graphite/Si combinations.
A practical solution is presented to increase the stability of 4.45 V LiCoO 2 via high-temperature Ni doping, without adding any extra synthesis step or cost. How a putative uniform bulk doping with highly soluble elements can profoundly modify the surface chemistry and structural stability is identified from systematic chemical and microstructural analyses. This modification has an electronic origin, where surface-oxygen-loss induced Co reduction that favors the tetrahedral site and causes damaging spinel phase formation is replaced by Ni reduction that favors octahedral site and creates a better cation-mixed structure. The findings of this study point to previously unspecified surface effects on the electrochemical performance of battery electrode materials hidden behind an extensively practiced bulk doping strategy. The new understanding of complex surface chemistry is expected to help develop higherenergy-density cathode materials for rechargeable batteries.
To meet a desire to the smaller and long-lasting battery for portable electronics and electric vehicles, it is of particular interest to achieve high energy density of lithium ion batteries (LIBs) for last decades. [1][2][3] Accordingly, sustained research effort has been dedicated to shifting the material paradigm from that of conventional intercalation-type active materials toward
To achieve the urgent requirement for high volumetric energy density in lithium-ion batteries, alloy-based anodes have been spotlighted as next-generation alternatives. Nonetheless, for the veritable accomplishment with regards to high-energy demand, alloy-based anodes must be evaluated considering several crucial factors that determine volumetric capacity. In particular, the electrode swelling upon cycling must be contemplated if these anodes are to replace conventional graphite anodes in terms of volumetric capacity. Herein, we propose macropore-coordinated graphite-silicon composite by incorporating simulation and mathematical calculation of numerical values from experimental data. This unique structure exhibits minimized electrode swelling comparable to conventional graphite under industrial electrode fabrication conditions. Consequently, this hybrid anode, even with high specific capacity (527 mAh g−1) and initial coulombic efficiency (93%) in half-cell, achieves higher volumetric capacity (493.9 mAh cm−3) and energy density (1825.7 Wh L−1) than conventional graphite (361.4 mAh cm−3 and 1376.3 Wh L−1) after 100 cycles in the full-cell configuration.
Pseudocapacitive materials have been highlighted as promising electrode materials to overcome slow diffusion‐limited redox mechanism in active materials, which impedes fast charging/discharging in energy storage devices. However, previously reported pseudocapacitive properties have been rarely used in lithium‐ion batteries (LIBs) and evaluation methods have been limited to those focused on thin‐film‐type electrodes. Hence, a nanocage‐shaped silicon–carbon composite anode is proposed with excellent pseudocapacitive qualities for LIB applications. This composite anode exhibits a superior rate capability compared to other Si‐based anodes, including commercial silicon nanoparticles, because of the higher pseudocapacitive contribution coming from ultrathin Si layer. Furthermore, unprecedent 3D pore design in cage shape, which prevents the particle scale expansion even after full lithiation demonstrates the high cycling stability. This concept can potentially be used to realize high‐power and high‐energy LIB anode materials.
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