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A lotus‐root‐like three‐dimensional mesoporous silicon is successfully prepared by a magnesiothermic reduction method using SBA‐15 silica as both template and silicon precursor. After carbon coating via a chemical vapor deposition process, this anode material shows high reversible capacity of ∼1900 mAh g−1 and excellent rate performance even up to 15C.

Hierarchical porous TiO(2)-B with thin nanosheets is successfully synthesized. TiO(2)-B polymorph ensures fast insertion of Li-ion due to its pseudocapacitive mechanism. The thin nanosheet walls with porous structure allow exposure to electrolytes for facile ionic transport and interfacial reaction. The joint advantages endow this material with high reversible capacity, excellent cycling performance, and superior rate capability.

In order to increase the energy content of lithium ion batteries (LIBs), researchers worldwide focus on high specific energy (Wh/kg) and energy density (Wh/L) anode and cathode materials. However, most of the attention is primarily paid to the specific gravimetric and/or volumetric capacities of these materials, while other key parameters are often neglected. For practical applications, in particular for large size battery cells, the Coulombic efficiency (CE), voltage efficiency (VE), and energy efficiency (EE) have to be considered, which we point out in this work by comparing numerous LIB active materials. For all presented active materials, energy inefficiency is mainly caused by a voltage inefficiency, which in turn is affected by the voltage hysteresis between the charge and discharge curves. Hence, this study could show that materials with larger voltage hysteresis such as the ZnFe 2 O 4 (ZFO) anode or the Lirich cathode material exhibit also a lower VE and EE than for instance graphite and LiNi 0.5 Mn 1.5 O 4 . Furthermore, from the accumulated EE losses the resulting "extra energy costs" are calculated based on industry and domestic electricity costs in Germany, in Japan and in the U.S.A. In particular, in countries with higher electricity costs such as Germany, the accumulated extra energy, which is necessary to compensate the energy inefficiency while retaining a certain energy level in the electrode material, has a stronger impact on the extra energy costs and thus on the total cost of ownership of the battery cell system.

The lithium (Li) metal battery (LMB) is one of the most promising candidates for next-generation energy storage systems. However, it is still a significant challenge to operate LMBs with high voltage cathodes under high rate conditions. In this work, an LMB using a nickel-rich layered cathode of LiNi 0.76 Mn 0.14 Co 0.10 O 2 (NMC76) and an optimized electrolyte [0.6 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) + 0.4 M lithium bis(oxalato)borate (LiBOB) + 0.05 M LiPF 6 dissolved in ethylene carbonate and ethyl methyl carbonate (EC:EMC, 4:6 by weight)] demonstratesexcellent stability at a high charge cutoff voltage of 4.5 V. Remarkably, these Li||NMC76 cells can deliver a high discharge capacity of >220 mAh g -1 (846 Wh kg -1 ) and retain more than 80% capacity after 1000 cycles at high charge/discharge current rates of 2C/2C (1C = 200 mA g -1 ). This excellent electrochemical performance can be attributed to the greatly enhanced structural/interfacial stability of both the Ni-rich NMC76 cathode material and the Li metal anode using the optimized electrolyte.

Porous structured silicon has been regarded as a promising candidate to overcome pulverization of silicon-based anodes. However, poor mechanical strength of these porous particles has limited their volumetric energy density towards practical applications. Here we design and synthesize hierarchical carbon-nanotube@silicon@carbon microspheres with both high porosity and extraordinary mechanical strength (>200 MPa) and a low apparent particle expansion of~40% upon full lithiation. The composite electrodes of carbon-nanotube@silicon@carbon-graphite with a practical loading (3 mAh cm −2) deliver~750 mAh g −1 specific capacity, <20% initial swelling at 100% state-of-charge, and~92% capacity retention over 500 cycles. Calendered electrodes achieve~980 mAh cm −3 volumetric capacity density and <50% end-of-life swell after 120 cycles. Full cells with LiNi 1/3 Mn 1/3 Co 1/3 O 2 cathodes demonstrate >92% capacity retention over 500 cycles. This work is a leap in silicon anode development and provides insights into the design of electrode materials for other batteries.

Lithium (Li) metal is a promising candidate as the anode for high‐energy‐density solid‐state batteries. However, interface issues, including large interfacial resistance and the generation of Li dendrites, have always frustrated the attempt to commercialize solid‐state Li metal batteries (SSLBs). Here, it is reported that infusing garnet‐type solid electrolytes (GSEs) with the air‐stable electrolyte Li3PO4 (LPO) dramatically reduces the interfacial resistance to ≈1 Ω cm2 and achieves a high critical current density of 2.2 mA cm−2 under ambient conditions due to the enhanced interfacial stability to the Li metal anode. The coated and infused LPO electrolytes not only improve the mechanical strength and Li‐ion conductivity of the grain boundaries, but also form a stable Li‐ion conductive but electron‐insulating LPO‐derived solid‐electrolyte interphase between the Li metal and the GSE. Consequently, the growth of Li dendrites is eliminated and the direct reduction of the GSE by Li metal over a long cycle life is prevented. This interface engineering approach together with grain‐boundary modification on GSEs represents a promising strategy to revolutionize the anode–electrolyte interface chemistry for SSLBs and provides a new design strategy for other types of solid‐state batteries.

electric vehicles. [1] LIBs with the conventional carbonaceous anode materials such as graphite have played a dominant role in the current market of customer electronics and electrical transportation. However, low capacity of carbonaceous anode materials (372 mAh g −1 ) also limits the further increase in energy densities of LIBs. [2] In this regard, silicon (Si)-based anode is considered as one of the most promising anode candidates in further boosting the specific energy of LIBs because Si has one of the highest practical capacity of 3579 mAh g −1 among various anode materials and a relatively low lithiation potential of 0.2 V versus Li/Li + . However, fast capacity fade and large swelling of Si anodes related to their large volume expansion (>300%) upon lithiation greatly hindered their deployment in practical applications. [3] There has been significant progress toward understanding and mitigating the capacity fade in Si-based anodes, including exploiting nanostructured Si materials, [4] porous structures, [5] surface coatings, [6] core-shell structures, [7] and novel binders. [8] However, the development of novel electrolytes for Si-based anodes is relatively slow because most researches have been focused on the structure development of Si electrodes. The conventional electrolytes for Si anodes are LiPF 6 /carbonate-based electrolytes with a certain amount of fluoroethylene carbonate (FEC) as an additive or cosolvent (from 5% to 10% by weight in the electrolytes). [9] Linear carbonate solvents usually have relatively low flashpoints, so they are easily ignited and may lead to safety problems under certain extreme conditions. [10] In addition, the formed solid electrolyte interphase (SEI) on anode surface in conventional carbonate electrolytes is unstable and cannot withstand the large volume changes of Si during cycling. Although the introduction of FEC in the conventional LiPF 6 / carbonate electrolytes can improve the cycling performance of Si anodes, increased amount of FEC may lead to increased gassing in full cells. Because such high content of FEC in the electrolytes may form a detrimental cathode electrolyte interface (CEI) on cathode surface and generate a serious gassing issue especially at high charge cutoff voltages and elevated temperatures, which lead to impedance increase, capacity fading and safety issue of the Si-based full cells. Therefore, the Silicon anodes are regarded as one of the most promising alternatives to graphite for high energy-density lithium-ion batteries (LIBs), but their practical applications have been hindered by high volume change, limited cycle life, and safety concerns. In this work, nonflammable localized highconcentration electrolytes (LHCEs) are developed for Si-based anodes. The LHCEs enable the Si anodes with significantly enhanced electrochemical performances comparing to conventional carbonate electrolytes with a high content of fluoroethylene carbonate (FEC). The LHCE with only 1.2 wt% FEC can further improve the long-term cycling stability of Si-base...