The ever increasing awareness of the environment and sustainability drives research to find new solutions in every part of society. In the transport sector, this has led to a goal of replacing the internal combustion engine (ICE) with an electrical engine that can be powered by renewable electricity. As a battery for vehicles, the Li-ion chemistries have become dominant due to their superior volumetric and gravimetric energy densities. While promising, electric vehicles require further improvements in terms of capacity and power output before they can truly replace their ICE counterparts. Another aspect is the CO2 emissions over lifetime, since the electric vehicle itself presently outlives its battery, making battery replacement necessary. If the lifetime of the battery could be increased, the life-cycle emissions would be significantly lowered, making the electric vehicle an even more suitable candidate for a sustainable society. In this context, lithium titanium oxide (LTO) has been suggested as a new anode material in heavy electric vehicles applications due to intrinsic properties regarding safety, lifetime and availability. The LTO battery chemistry is, however, not fully understood and fundamental research is necessary for future improvements. The scope of this project is to investigate degradation mechanisms in LTO-based batteries to be able to mitigate these and prolong the device lifetime so that, in the end, a suitable chemistry for large scale applications can be suggested. The work presented in this licentiate thesis is focused on the LTO electrode/electrolyte interface. Photoelectron spectroscopy (PES) was applied to determine whether the usage of LTO would prevent anode-side electrolyte decomposition, as suggested from the intercalation potential being inside the electrochemical stability window of common electrolytes. It has been found that electrolyte decomposition indeed occurs, with mostly hydrocarbons of ethers, carboxylates, and some inorganic lithium fluoride as decomposition products, and that this decomposition to some extent ensued irrespective of electrochemical battery operation activity. Second, an investigation into how crossover of manganese ions from Mn-based cathodes influences this interfacial layer has been conducted. It was found, using a combination of high-energy x-ray photoelectron spectroscopy (HAXPES) and near-edge x-ray absorption fine structure (NEXAFS) that although manganese is present on the LTO anode surface when paired with a common manganese oxide spinel cathode, the manganese does little to alter the surface chemistry of the LTO electrode.

Silicon (in the form of lithium silicides) has almost ten times the theoretical charge storage capacity of graphite, the anode material used in most commercially-available lithium-ion batteries. Replacing graphite with silicon therefore promises a substantial improvement over the state-of-the-art in electrochemical energy storage. However, it has proved difficult to realise this high theoretical capacity in a practical electrochemical cell and maintain it over repeated charge-discharge cycles. This dissertation presents experimental work probing the changes in local structure occurring during the electrochemical reactions of lithium with silicon, using neutron total scattering and nuclear magnetic resonance, together with novel processing methodologies for analysing the resulting data, in the hope of suggesting ways of improving the performance of silicon-based lithium-ion batteries. Neutron total scattering patterns were obtained from silicon-based anode materials extracted from cells at various states of charge. These samples were composed of a heterogeneous mixture of amorphous, crystalline and disordered crystalline materials. Reverse Monte Carlo is a technique for obtaining structural information from experimental data (particularly total scattering patterns) from amorphous and disordered crystalline materials. However, previously existing Reverse Monte Carlo software could only handle homogeneous materials. Therefore, the RMCprofile software package was extended to handle data from heterogeneous samples. The improved RMCprofile was applied to the aforementioned total scattering patterns, but the much stronger scattering from the other components (themselves not well-characterised) swamped that from the lithium silicide. Future work should attempt to reduce the scattering from the inactive components, particularly the hard-to-model incoherent scattering. NMR data were acquired in situ from silicon-nanowire-based lithium-ion batteries during repeated charge-discharge cycles, achieving much better electrochemical performance than had been seen in previous in situ experiments with silicon. Owing to the large quantities of data obtained, an automated, model-free dimensionality reduction technique was needed. The NMR data were processed using principal component analysis and a variant of non-negative matrix factorisation. With both of these methods, one of the components was found to be associated with high voltages vs. ${Li \vert{} Li^{+}}$ (i.e. a fully discharged anode). This region has seen very little interest by comparison with the low voltage (high levels of lithiation) region of the charge-discharge cycle, so this discovery suggests a new avenue for future research.

Lithium-ion batteries (LIBs) are an integral part of consumer electronic devices and electric vehicles. There is a growing need for LIBs with higher capacity, rate performance and cycling stability. At the anode electrode these challenges are being addressed for instance by utilising materials with higher theoretical capacity compared to graphite (372 mAh/g) or by optimising the morphology of materials through nanostructuring of the electrode. In this thesis the former is investigated by synthesising a reduced graphene oxide (rGO) tin sulphide (SnS2) hybrid, and the latter by self-assembly of rGO sodium titanate and rGO titanium dioxide (TiO2) nanorods. In Chapter 2, SnS2 is investigated due to its high theoretical capacity as an anode material (645 mAh/g), low cost and environmental benignity. SnS2 nanoparticles were grown directly on rGO sheets which provide a conductive framework and limit the detachment of tin particles which undergo large volume changes during alloying reactions. However, a fast decrease in capacity was observed. Post-mortem analysis of the electrodes showed that rGO becomes irreversibly passivated suggesting that additional measures to retain effective charge transport between the low weight percent conductive additive and the active phase during cycling are required. An alternative material system based on nanorods of intercalation materials (sodium titanate and TiO2) wrapped by rGO sheets was chosen to investigate self-assembly in anodes to address the low packing density of nanomaterials. A drop-casting method was used to align rGO-sodium titanate nanorods through evaporation driven self-assembly (Chapter 3) which relies on a combination of electrostatic repulsive forces originating from the rGO coating, and liquid crystal phase formation at high concentrations, facilitated by the high aspect ratio nanorods. As reference, non-aligned films were prepared by adjusting the pH of the nanorod dispersion. Freestanding aligned and non-aligned films were converted to rGO-TiO2 (Chapter 4). The volumetric capacity of the self-assembled films was double that of non-aligned films, and up to 4.5 times higher than traditional casted electrodes using the same material. Further, up to rates of 4 C, the self-assembled films outperformed the non-aligned films. These films showed no sign of capacity fading up to 1000 cycles, which together with post-mortem analysis confirms that these assembled structures are maintained during battery cycling.

With the rapid growth of the world population and the process of industrialization of modern society, the demand for energy continues to rise sharply. There is a pessimistic prediction that a peak of consumption primarily fossil fuels will happen in the 2020s to 2030s, hence it is urgent to develop alternative renewable clean energy sources before this coming energy crisis. But the availability of renewable clean energy always is discontinuous, uncontrollable, and unstable. Besides, the generated renewable energy cannot be used directly. Therefore, an energy storage system is urgently needed as the medium to harvest and store the energy generated from the intermittent renewable resource, and also to regulate the electricity output, and improve the tolerance ability of the power grid to renewable energy. Rechargeable aqueous zinc-ion battery, especially those that use mild electrolytes, is drawing more and more attention in the past decades and is regarded as the most promising candidate for large-scale energy storage systems. Compared with the widely used lithium-ion battery which dominated the commercial energy market now, the aqueous zinc-ion battery holds the merits of high theoretical capacity (820 mAh/g gravimetric capacity and 5855 mAh/m3 volumetric capacity), low electrochemical potential (-0.763 V vs. SHE) and high energy density due to the two-electron redox reaction, high abundance in the earth crust and high mass production, low toxicity, and environmental benignity, and the most valuable advantage intrinsic safety in aqueous electrolyte. In this dissertation, the first part focuses on the preliminary application of an aqueous zinc-ion battery. One kind of planar on-chip aqueous zinc-ion micro-battery with high-rate performance was designed and fabricated. The PEDOT and MnO2 cathode can suppress the dissolution of electrode material which can highly improve the cycling performance of the micro-battery. The as-prepared micro-battery displays a high specific capacity of 25.8 μAh/cm2 after 25 activation cycles at a current density of 1 mA/cm2. A reversible specific capacity of 6.2 μAh/cm2 is achieved after 200 cycles, with 55.4 % of the initial discharge capacity retention. To improve the cycling performance of the aqueous zinc-ion battery, the second part of this thesis is preparing a highly enhanced reversibility Zn anode by in-situ texturing. The crystal plane (002)-textured Zn anode with an ultrathin passivation layer suppressed the Zn corrosion and enhanced the full battery performance. Based on these merits, the cycling stability of the Zn anode is enhanced from 791 hours to more than 1500 hours. The coulombic efficiency (CE) of a Zn||Ti asymmetric cell is greater than 90% over 500-hour cycles. For the Zn||MnO2 full cell, the addition of H3PO4 into the electrolyte improves both the rate capability and cycling stability of Zn||MnO2 cells. More importantly, a highly reversible Zn||O2 full cell is demonstrated at a large depth of discharge of Zn (DODZn > 10%), projecting the lower bounds of the cell-level specific energy of lithium-ion batteries.:Abstract I Kurzfassung III List of Abbreviations IX Chapter 1 Background and motivation 1 1.1 Research motivation 1 1.2 Aim of this dissertation 2 1.3 Dissertation structure 3 Chapter 2 Introduction of aqueous zinc-ion battery and anode protection strategies 5 2.1 Introduction of aqueous zinc-ion battery 5 2.2 The challenges of zinc anode 8 2.2.1 Dendrites and protrusion 9 2.2.2 Hydrogen evolution reaction 10 2.2.3 Passivation layer 10 2.3 The strategies of zinc anode protection 11 2.3.1 Surface engineering 11 2.3.2 Electrolyte modification 15 2.3.3 3D structural skeleton and alloy strategies 22 Chapter 3 Experiment characterizations and calculations 25 3.1 Electrochemical methods 25 3.1.1 Chronoamperometry 25 3.1.2 Chronopotentiometry 26 3.1.3 Cyclic voltammetry 27 3.1.4 Galvanostatic charge/discharge 28 3.1.5 Electrochemical impedance spectroscopy 29 3.1.6 Tafel measurement 30 3.2 Characterization methods 31 3.2.1 X-ray diffraction 31 3.2.2 Scanning electron microscope 32 3.2.3 X-ray photoelectron spectroscopy 32 3.2.4 Raman spectroscopy 33 3.3 Experimental calculations 34 3.3.1 b value calculation 34 3.3.2 CE calculation 34 3.3.3 RTC calculation 35 3.3.4 DFT calculation 36 3.3.5 DOD calculation 37 3.3.6 Corrosion rate calculation 38 Chapter 4 A planar on-chip aqueous zinc-ion micro-battery with high-rate performance 41 4.1 Introduction 41 4.2 Experimental section 43 4.2.1 Interdigitated electrodes 43 4.2.2 Preparation of micro-battery 44 4.2.3 Microstructural properties characterization 45 4.2.4 Electrochemical characterization 45 4.3 Results and discussion 46 4.3.1 Characterization of micro-battery 46 4.3.2 Electrochemical performance measurement 49 4.4 Conclusions 56 Chapter 5 Highly enhanced reversibility of a Zn anode by in-situ texturing 57 5.1 Introduction 57 5.2 Experimental section 63 5.2.1 Preparation of the textured Zn anode 63 5.2.2 Synthesis of cathode materials 63 5.2.3 Electrochemical and material characterizations 64 5.3 Results and discussions 64 5.3.1 Nonuniform Zn deposition on an epitaxial substrate 65 5.3.2 In-situ texturing and SEI formation during the cycling 72 5.3.3 Full-cell performance 77 5.4 Conclusions 81 Chapter 6 Summary and outlook 83 6.1 Summary 83 6.2 Outlook 84 References： 87 Acknowledgment 99 Publications 101 Curriculum Vitae 103 Selbstständigkeitserklärung 105

Master of Science / Mechanical and Nuclear Engineering / Kevin B. Lease / Gurpreet Singh / Energy has always been one of the most important factors in any type of human or industrial endeavor. Clean energy and alternative energy sources are slowly but steadily replacing fossil fuels, the over-dependence on which have led to many environmental and economic troubles over the past century. The main challenge that needs to be addressed in switching to clean energy is storing it for use in the electrical grid and transportation systems. Lithium ion batteries are currently one of the most promising energy storage devices and tremendous amount of research is being done in high capacity anode and cathode materials, and better electrolytes and battery packs as well, leading to overall high efficiency and capacity energy storage systems. Polymer derived ceramics (PDCs) are a special class of ceramics, usually used in high temperature applications, but some silicon based PDCs have demonstrated good electrochemical properties in lithium ion batteries. The goal of this research is to explore a special hybrid ceramic of titanium dioxide (TiO₂) and silicon oxy carbide (SiOC) ceramic derived from 1,3,5,7 -- tetravinyl -- 1,3,5,7 -- tetramethylcyclotetrasiloxane (TTCS) polymer for use in lithium ion batteries and investigate the source of its properties which might make the ceramic particularly useful in some highly specialized energy storage applications.

Self-activation is a process that takes advantage of the gases emitted from the pyrolysis process of biomass to activate the converted carbon. The pyrolytic gases from the biomass contain CO2 and H2O, which can be used as activating agents. As two common methods, both of physical activation using CO2 and chemical activation using ZnCl2 introduce additional gas (CO2) or chemical (ZnCl2), in which the CO2 emission from the activation process or the zinc compound removal by acid from the follow-up process will cause environmental concerns. In comparison with these conventional activation processes, the self-activation process could avoid the cost of activating agents and is more environmentally friendly, since the exhaust gases (CO and H2) can be used as fuel or feedstock for the further synthesis in methanol production. In this research, many types of biomass were successfully converted into activated carbon through the self-activation process. An activation model was developed to describe the changes of specific surface area and pore volume during the activation. The relationships between the activating temperature, dwelling time, yield, specific surface area, and specific pore volume were detailed investigated. The highest specific surface area and pore volume of the biomass-derived activated carbon through the self-activation process were up to 2738 m2 g-1 and 2.209 cm3 g-1, respectively. Moreover, the applications of the activated carbons from the self-activation process have been studied, including lithium-ion battery (LIB) manufacturing, water cleaning, oil absorption, and electromagnetic interference (EMI) shielding.

Despite the central importance of porous electrodes to any advanced electrochemical system, there is no clear answer to “<i>How to make the best electrode</i>?”. The source of ambiguity lies in the incomplete understanding of convoluted material interactions at smaller – difficult to observe length and timescales. Such mesoscopic interactions, however, abide by the fundamental physical principles such as mass conservation. The porous electrodes are investigated in such a physics-based setting to comprehend the interplay among structural arrangement and off-equilibrium processes. As a result, a synergistic approach exploiting the complementary characteristics of controlled experiments and theoretical analysis emerges to allow mechanistic insights into the associated mesoscopic phenomena. The potential of this philosophy is presented by investigating three distinct electrochemical systems with their unique peculiarities.

Die vorliegende Arbeit liefert einen Beitrag für ein besseres Verständnis über die zyklische Alterung von Siliciumnanopartikel (Si-NP) als Anodenmaterial in Lithium-Ionen- und Lithium-Schwefel-Batterien. Im Fokus der Studie stand der Einfluss der Partikelgröße, des Elektrodendesigns und der Elektrolytzusammensetzung auf die elektrochemische Reversibilität des Siliciums zur Lithiumspeicherung. Über umfangreiche strukturelle Charakterisierungstechniken mittels Röntgenbeugung, Elektronenmikroskopie und der Röntgenphotoelektronenspektroskopie in Verbindung mit elektrochemischen Untersuchungsmethoden, konnten wesentliche Mechanismen zur Degradation aufgeklärt und die Funktion diverser Oberflächenverbindungen auf der Siliciumanode identifiziert werden. Als Hauptursache der Degradation von Si-NP mit einer Partikelgröße unter 20 nm konnte das Wachstum der Solid-Electrolyte-Interface (SEI) identifiziert werden. Pulverisierung und die Bildung neuer kristalliner Phasen kann ausgeschlossen werden. Es wurde ein kostengünstiges und flexibles Verfahren zur Herstellung eines nanostrukturierten Silicium-Kohlenstoff-Komposites entwickelt, welches unter optimierten Bedingungen eine spezifische Kapazität von 1280 mAh/g(Elektrode) und einen Kapazitätserhalt von 81 % über 500 Tiefentladungszyklen liefert. Es konnten erfolgreich hoch reversible Flächenkapazitäten von 5 mAh/cm^2 bei nur 4,4 mg/cm^2 Elektrodengewicht nachgewiesen werden. Für die Arbeit wurde zunächst ein Verfahren zur Herstellung von monodispersen Si-NP mit einer Größe von 5 nm – 20 nm angewendet. Die galvanostatische Zyklierung gegen Lithiummetall hat ergeben, dass mit abnehmender Partikelgröße die Reversibilität des Siliciums zunimmt. Über in situ Synchrotron XRD und post mortem XPS konnte eine stabilere Solid-Electrolyte-Interface (SEI) mit abnehmender Partikelgröße als Hauptursache identifiziert werden. Im weiteren Verlauf der Arbeit wurden Si-NP im porösen Kohlenstoffgerüst durch ein leicht modifiziertes Herstellungsverfahren abgeschieden und untersucht. Durch das veränderte Elektrodendesign konnte die Reversibilität bei gleichem Kohlenstoffgehalt deutlich verbessert werden, da der Kontaktverlust des Siliciums zum leitfähigen Gerüst durch SEI Wachstum verzögert wird. Die Elektrolytadditive Fluoroethylencarbonat und Vinylencarbonat führen zu einer weiteren Verbesserung der Reversibilität, wobei Vinylencarbonat die höchste Reversibilität zur Folge hat, jedoch einen hohen Filmwiderstand verursacht. Weiterhin wurden etherbasierte Elektrolyte, welche typischerweise in Lithium-Schwefel-Batterien zum Einsatz kommen, untersucht. Hierbei wurde eine positive Wirkung von Lithiumnitrat auf die Reversibilität von Silicium festgestellt. Es konnten erfolgreich Si-Li-S (SLS) Vollzellen getestet werden, welche eine höhere Lebensdauer als vergleichbare Zellen mit Lithiummetall als Anode aufweisen. Aus den elektrochemischen und post mortem Untersuchungen konnte ein positiver Einfluss von Polysulfiden auf die SEI von Silicium nachgewiesen werden. Durch die umfangreichen post mortem Analysen konnte die Funktion diverser, in der SEI des Siliciums auftretender Verbindungen in Abhängigkeit der Elektrolytzusammensetzung aufgeklärt werden. Es wurde ein anschaulicher Mechanismus des SEI Wachstums in Abhängigkeit des Elektrolyts erstellt. / The results of this work provide a better understanding about the cyclic aging of silicon nanoparticles (Si-NP) as anode material in Lithium-ion- and Lithium-sulfur batteries. Subject of investigation was the influence of particle size, electrode design and electrolyte composition on the electrochemical reversibility of Si-NP for lithium storage. The main characterization techniques used in this study were XRD, SEM, TEM and XPS combined with electrochemical analysis and in situ synchrotron XRD. Bare silicon nanoparticles ranging from 5 – 20 nm and silicon nanoparticles embedded within a porous carbon scaffold were prepared through a cost-effective and novel synthesis technique including the hydrolysis of trichlorosilane as feedstock. The dominant degradation mechanism of these silicon nanoparticles was identified to be the continuous growth the solid-electrolyte-interphase (SEI). Other phenomena such as pulverisation or new evolving crystalline phases are excluded. It was found that a reduction of the particle size from 20 nm to 5 nm increases the reversibility due to a thicker and therewith more stable SEI. The deposition of the silicon nanoparticles into a porous carbon scaffold caused a significant improvement of the reversibility at constant carbon content. The effect of the electrolyte additives Fluoroethylene carbonate and Vinylene carbonate was analysed in detail. Furthermore, typical electrolyte compositions used for lithium-sulfur-batteries were tested and studied. Si-Li-S (SLS) full cells were demonstrated which outperform conventional lithium-sulfur batteries in terms of life time. The systematic analysis and the rational optimization process of the particle size, electrode design and electrolyte composition allowed to provide a nanostructured silicon electrode with a specific capacity of up to 1280 mAh/g(Electrode) and 81 % capacity retention after 500 deep discharge cycles. Reversible areal capacities of 5 mAh/cm^2 at 4.4 mg/cm^2 electrode weight were demonstrated.

Hochleistungsfähige Lithium-Ionen-Batterien sind insbesondere von der hohen spezifischen Kapazität ihrer Elektrodenmaterialien abhängig. Intermetallische Phasen sind vielversprechende Kandidaten für alternative Anodenmaterialien mit verbesserten spezifischen Kapazitäten (LiAl: 993 Ah/kg; Li22Si5: 4191 Ah/kg) gegenüber den derzeit vielfach verwendeten Kohlenstoff-Materialien (LiC6: 372 Ah/kg). Nachteilig ist jedoch, dass die kristallinen Phasenumwandlungen während der Lade-Entlade-Prozesse Volumenänderungen von 100-300% verursachen. Durch die Sprödigkeit der intermetallischen Phasen führt dies zum Zerbrechen des Elektrodenmaterials und damit zum Kontaktverlust. Um Lithiierungs- und Delithiierunsprozesse ohne kristalline Phasenumwandlungen zu realisieren und somit große Volumenänderungen zu vermeiden, wurden amorphe Al-Legierungen untersucht. In amorphe, mittels Schmelzspinnen hergestellte Legierungen (Al86Ni8La6 und Al86Ni8Y6) kann beim galvanostatischen Zyklieren nur sehr wenig Li eingelagert werden. Da kristalline Phasenumwandlungen im amorphen Zustand nicht möglich sind, wird für die Diffusion und Einlagerung von Li-Ionen ein ausreichendes freies Volumen im amorphen Atomgerüst benötigt. Die Dichtemessung der Legierungen zeigt, dass dieses freie Volumen für eine signifikante Lithiierung nicht ausreichend ist. Wird Li bereits in die amorphe Ausgangslegierung integriert, können Li-Ionen auf elektrochemischem Wege aus ihr entfernt und auch wieder eingebaut werden. Die neuartige Legierung Al43Li43Ni8Y6, die Li bereits im Ausgangszustand enthält, konnte mittels Hochenergiemahlung als amorphes Pulver hergestellt werden. Verglichen mit den Li-freien amorphen Legierungen Al86Ni8La6 bzw. Al86Ni8Y6 und ihren kristallisierten Pendants zeigt diese neu entwickelte, amorphe Legierung eine signifikant höhere Lithiierungsfähigkeit und erreicht damit eine spezifische Kapazität von ca. 800 Ah/kg bezogen auf den Al-Anteil. Durch den Abrieb des Stahlmahlbechers enthält das Pulver Al43Li43Ni8Y6 einen Fe-Anteil von ca. 15 Masse%. Dieses mit Fe verunreinigte Material zeigt besonders bei niedrigen Laderaten eine bessere Zyklenstabilität als ein im abriebfesten Siliziumnitrid-Becher gemahlenes Pulver der gleichen Zusammensetzung. Mittels Mössbauerspektroskopie wurde nachgewiesen, dass das Pulver z.T. oxidisches Fe enthält. Dieses kann über Konversionsmechanismen einen Beitrag zur spezifischen Kapazität leisten. / High-energy Li-ion batteries exceedingly depend on the high specific capacity of electrode materials. Intermetallic alloys are promising candidates to be alternative anode materials with enhanced specific capacities (LiAl: 993 Ah/kg; Li22Si5: 4191 Ah/kg) in contrast to state-of-the-art techniques, dominated by carbon materials (LiC6: 372 Ah/kg). Disadvantageously the phase transitions during the charge-discharge processes, induced by the lithiation process, cause volume changes of 100-300 %. Due to the brittleness of intermetallic phases, the fracturing of the electrode material leads to the loss of the electrical contact. In order to overcome the huge volume changes amorphous Al-based alloys were investigated with the intension to realize the lithiation process without a phase transformation. Amorphous powders (Al86Ni8La6 and Al86Ni8Y6) produced via melt spinning and subsequent ball milling only show a minor lithiation during the electrochemical cycling process. This is mainly caused by the insufficient free volume, which is necessary to transfer and store Li-ions, since phase transitions are impossible in the amorphous state. If Li is already integrated into the amorphous alloy, Li-ions can easily be removed and inserted electrochemically. The new alloy Al43Li43Ni8Y6 contains Li already in its initial state and could be prepared by high energy milling as an amorphous powder. Compared with the Li-free amorphous alloys Al86Ni8La6 or Al86Ni8Y6 and their crystalline counterparts, this newly developed amorphous alloy achieves a significantly higher lithiation and therefore reaches a specific capacity of 800 Ah/kg, based on the Al-content. By the abrasion of the steel milling vials the powder contains a wear debris of 15 mass% Fe. This contaminated material shows a better cycling stability than a powder of the same composition, milled in a non-abrasive silicon nitride vial. By means of Mössbauer spectroscopy has been shown that the wear debris contains Fe oxides. This may contribute to the enhancement of the specific capacity about conversion mechanisms.

Porous carbons are promising anode materials for next generation lithium batteries due to their large lithium storage capacities. However, their highsloping capacity during lithiation and delithiation as well as capacity fading due to intense formation of solid electrolyte interphase (SEI) limit their gravimetric and volumetric energy densities. Herein we compare a microporous carbide derived carbon material (MPC) as promising future anode for all solid state batteries with a commercial high performance hard carbon anode. The MPC obtains high and reversible lithiation capacities of 1000 mAh g 1 carbon in half cells exhibiting an extended plateau region near 0 V vs. Li/Liþ preferable for full cell application. The well defined microporosity of the MPC with a specific surface area of >1500 m2 g 1 combines well with the argyrodite type electrolyte (Li6PS5Cl) suppressing extensive SEI formation to deliver high coulombic efficiencies. Preliminary full cell measurements vs. nickel rich NMC cathodes (LiNi0.9Co0.05Mn0.05O2) provide a considerably improved average potential of 3.76 V leading to a projected energy density as high as 449 Wh kg 1 and reversible cycling for more than 60 cycles. 7Li Nuclear Magnetic Resonance spectroscopy was combined with ex situ Small Angle X ray Scattering to elucidate the storage mechanism of lithium inside the carbon matrix. The formation of extended quasi metallic lithium clusters after electrochemical lithiation was revealed.