NiO is a highly appealing anode material for lithium-ion batteries (LIBs) owing to its relatively high Li storage capacity. However, its low electrical conductivity and large volume change during the battery cycling process limit its application. Here, we fabricate a series of porous Ni/NiO (M) nanocomposites through the direct pyrolysis of a nickel oxalate precursor and adjust the Ni(0) content by varying the pyrolysis temperature. The porous architecture is beneficial for alleviating the volume expansion/constriction during cycling. The Ni in the composites accelerates the electrochemical reaction kinetics and enhances the conductivity of the electrode materials. The M-2 electrode with a 17.9% Ni(0) content realizes a high reversible capacity (633.7 mA h g(-1) after 100 cycles at 0.2 A g(-1)) and exhibits outstanding rate capability (307.6 mA h g(-1) after 250 cycles at 1 A g(-1)). This work can not only supply an approach to adjust the content of an element with specific valence state, but also provide an inspiration for the fabrication of porous metal/metal oxide anode materials in LIBs. (C) 2020 Elsevier Inc. All rights reserved.