In-situ-grown hierarchical mesoporous Li 3 VO 4 on GO as a viable anode material for lithium ion batteries NISHANT GAUTAM 1 , VIJAY ALWERA 1 , RAEESH MUHAMMAD 1 , HARI RAJ 2 , MEGHA GOYAL 3 , ANJAN SIL 2 , PARITOSH MOHANTY 1 and TAPAS KUMAR MANDAL 1,3, * 1 Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India 2 Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, India 3 Centre of Nanotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India *Author for correspondence (tapasfcy@iitr.ac.in) MS received 7 April 2020; accepted 5 October 2020 Abstract. A simple and template-free one-pot solvothermal method is developed to grow hierarchical mesoporous Li 3 VO 4 (HM-Li 3 VO 4 ) on graphene oxide (GO). The growth of nutshell-shaped Li 3 VO 4 on GO with nutshell sizes ranging from 2 micrometres to sub-micrometre levels and a multimodal mesopore hierarchy lead to enhanced electrical and ionic conductivity of HM-Li 3 VO 4 -GO as compared to that of HM-Li 3 VO 4 or non-porous solid-state prepared Li 3 VO 4 alone. The composite material shows a charge capacity of 559 mAh g -1 at 0.1 C for the first cycle and a discharge capacity of 414 mAh g -1 at 0.5 C in the second cycle between 0.2 and 3 V. Furthermore, discharge capacity of 374 mAh g -1 achieved at 0.5 C in the fifth cycle is comparable or superior to those reported for other Li 3 VO 4 samples with similar carbon contents. The superior anode performance is attributed to its mesopore hierarchy and attachment with GO. Keywords. Hierarchical mesoporous Li 3 VO 4 ; Li 3 VO 4 -GO; one-pot hydro-solvothermal synthesis; anode material; electrochemical performance. 1. Introduction High energy density and high rate capability are probably the two major requirements along with safety for the Li-ion batteries to be used in electric vehicles (EVs), hybrid electric vehicles (HEVs) and plug-in hybrid electric vehi- cles (PHEVs). Although Li-ion batteries provide high gravimetric and volumetric energy densities [1–5], they can further be improved by developing new high capacity cathode and anode materials. Furthermore, the decomposi- tion of conventional electrolytes above 4.2 V is again one of the main obstacles in the development of high voltage cathode materials [6–8]. Although graphite is the workhorse among the anode materials used in Li-ion batteries, but certain safety issues, such as, dendritic growth of Li (due to low operational voltage *0.2 V) on the surface of graphite when charged at high rates, limits its use in large size Li-ion batteries [9]. Li 4 Ti 5 O 12 , on the other hand, has emerged as a competitor of graphite anode due to its highly flat plateau at 1.5 V vs. Li ? /Li and minimal volume change during lithium intercalation [10]. However, the low theoretical capacity (*170 mAh g -1 ) and high operating potential (*1.5 V) of Li 4 Ti 5 O 12 anode results in low energy and power density of Li-ion batteries. Therefore, an anode material with high capacity and safe charge–discharge cycles over a long period is essential for vehicular application. Thus, when combined with high voltage, a battery with high capacity can provide high energy density for longer driving distance on a single charge, while fast rate capability may allow faster recharge in charging stations like refueling on the way and extend the mileage. In our previous work [11], we have reported the synthesis of hierarchical mesoporous Li 3 VO 4 , wherein the meso- porous microstructure and the pore hierarchy have enabled to achieve enhanced Li-ion mobility and thereby improved electrochemical performance of Li 3 VO 4 as compared to most of the Li 3 VO 4 reported in its pure form (without carbon composite). However, the electrical conductivity remained poor thus leading to capacity fading with cycling and low discharge capacity at higher C rates. Efforts are being made by several research groups to improve both the ionic and electrical conductivity of Li 3 VO 4 to achieve high capacity retention and fast rate capability [12–18]. A number of articles have reported the synthesis of dif- ferent types of carbon composites with Li 3 VO 4 to enhance the electrical conductivity for better electrochemical Electronic supplementary material: The online version of this article (https://doi.org/10.1007/s12034-020-02271-8) contains supple- mentary material, which is available to authorized users. Bull Mater Sci (2020)43:292 Ó Indian Academy of Sciences https://doi.org/10.1007/s12034-020-02271-8